diff --git a/components/canvas/webgl_thread.rs b/components/canvas/webgl_thread.rs
index a90c996f8bb..4c6deace945 100644
--- a/components/canvas/webgl_thread.rs
+++ b/components/canvas/webgl_thread.rs
@@ -646,8 +646,9 @@ impl WebGLImpl {
                 ctx.gl().attach_shader(program_id.get(), shader_id.get()),
             WebGLCommand::DetachShader(program_id, shader_id) =>
                 ctx.gl().detach_shader(program_id.get(), shader_id.get()),
-            WebGLCommand::BindAttribLocation(program_id, index, ref name) =>
-                ctx.gl().bind_attrib_location(program_id.get(), index, name),
+            WebGLCommand::BindAttribLocation(program_id, index, ref name) => {
+                ctx.gl().bind_attrib_location(program_id.get(), index, &to_name_in_compiled_shader(name))
+            }
             WebGLCommand::BlendColor(r, g, b, a) =>
                 ctx.gl().blend_color(r, g, b, a),
             WebGLCommand::BlendEquation(mode) =>
@@ -736,10 +737,6 @@ impl WebGLImpl {
                 ctx.gl().stencil_op(fail, zfail, zpass),
             WebGLCommand::StencilOpSeparate(face, fail, zfail, zpass) =>
                 ctx.gl().stencil_op_separate(face, fail, zfail, zpass),
-            WebGLCommand::GetActiveAttrib(program_id, index, ref chan) =>
-                Self::active_attrib(ctx.gl(), program_id, index, chan),
-            WebGLCommand::GetActiveUniform(program_id, index, ref chan) =>
-                Self::active_uniform(ctx.gl(), program_id, index, chan),
             WebGLCommand::GetRenderbufferParameter(target, pname, ref chan) =>
                 Self::get_renderbuffer_parameter(ctx.gl(), target, pname, chan),
             WebGLCommand::GetFramebufferAttachmentParameter(target, attachment, pname, ref chan) =>
@@ -820,12 +817,15 @@ impl WebGLImpl {
                 ctx.gl().uniform_4i(uniform_id, x, y, z, w),
             WebGLCommand::Uniform4iv(uniform_id, ref v) =>
                 ctx.gl().uniform_4iv(uniform_id, v),
-            WebGLCommand::UniformMatrix2fv(uniform_id, transpose,  ref v) =>
-                ctx.gl().uniform_matrix_2fv(uniform_id, transpose, v),
-            WebGLCommand::UniformMatrix3fv(uniform_id, transpose,  ref v) =>
-                ctx.gl().uniform_matrix_3fv(uniform_id, transpose, v),
-            WebGLCommand::UniformMatrix4fv(uniform_id, transpose,  ref v) =>
-                ctx.gl().uniform_matrix_4fv(uniform_id, transpose, v),
+            WebGLCommand::UniformMatrix2fv(uniform_id, ref v) => {
+                ctx.gl().uniform_matrix_2fv(uniform_id, false, v)
+            }
+            WebGLCommand::UniformMatrix3fv(uniform_id, ref v) => {
+                ctx.gl().uniform_matrix_3fv(uniform_id, false, v)
+            }
+            WebGLCommand::UniformMatrix4fv(uniform_id, ref v) => {
+                ctx.gl().uniform_matrix_4fv(uniform_id, false, v)
+            }
             WebGLCommand::ValidateProgram(program_id) =>
                 ctx.gl().validate_program(program_id.get()),
             WebGLCommand::VertexAttrib(attrib_id, x, y, z, w) =>
@@ -1003,6 +1003,7 @@ impl WebGLImpl {
             return ProgramLinkInfo {
                 linked: false,
                 active_attribs: vec![].into(),
+                active_uniforms: vec![].into(),
             }
         }
 
@@ -1011,6 +1012,8 @@ impl WebGLImpl {
             gl.get_program_iv(program.get(), gl::ACTIVE_ATTRIBUTES, &mut num_active_attribs);
         }
         let active_attribs = (0..num_active_attribs[0] as u32).map(|i| {
+            // FIXME(nox): This allocates strings sometimes for nothing
+            // and the gleam method keeps getting ACTIVE_ATTRIBUTE_MAX_LENGTH.
             let (size, type_, name) = gl.get_active_attrib(program.get(), i);
             let location = if name.starts_with("gl_") {
                 -1
@@ -1025,9 +1028,31 @@ impl WebGLImpl {
             }
         }).collect::<Vec<_>>().into();
 
+        let mut num_active_uniforms = [0];
+        unsafe {
+            gl.get_program_iv(program.get(), gl::ACTIVE_UNIFORMS, &mut num_active_uniforms);
+        }
+        let active_uniforms = (0..num_active_uniforms[0] as u32).map(|i| {
+            // FIXME(nox): This allocates strings sometimes for nothing
+            // and the gleam method keeps getting ACTIVE_UNIFORM_MAX_LENGTH.
+            let (size, type_, mut name) = gl.get_active_uniform(program.get(), i);
+            let is_array = name.ends_with("[0]");
+            if is_array {
+                // FIXME(nox): NLL
+                let len = name.len();
+                name.truncate(len - 3);
+            }
+            ActiveUniformInfo {
+                base_name: from_name_in_compiled_shader(&name).into(),
+                size: if is_array { Some(size) } else { None },
+                type_,
+            }
+        }).collect::<Vec<_>>().into();
+
         ProgramLinkInfo {
             linked: true,
             active_attribs,
+            active_uniforms,
         }
     }
 
@@ -1045,42 +1070,6 @@ impl WebGLImpl {
       chan.send(result.into()).unwrap()
     }
 
-    #[allow(unsafe_code)]
-    fn active_attrib(
-        gl: &gl::Gl,
-        program_id: WebGLProgramId,
-        index: u32,
-        chan: &WebGLSender<WebGLResult<(i32, u32, String)>>,
-    ) {
-        let mut max = [0];
-        unsafe {
-            gl.get_program_iv(program_id.get(), gl::ACTIVE_ATTRIBUTES, &mut max);
-        }
-        let result = if index >= max[0] as u32 {
-            Err(WebGLError::InvalidValue)
-        } else {
-            Ok(gl.get_active_attrib(program_id.get(), index))
-        };
-        chan.send(result).unwrap();
-    }
-
-    #[allow(unsafe_code)]
-    fn active_uniform(gl: &gl::Gl,
-                      program_id: WebGLProgramId,
-                      index: u32,
-                      chan: &WebGLSender<WebGLResult<(i32, u32, String)>>) {
-        let mut max = [0];
-        unsafe {
-            gl.get_program_iv(program_id.get(), gl::ACTIVE_UNIFORMS, &mut max);
-        }
-        let result = if index >= max[0] as u32 {
-            Err(WebGLError::InvalidValue)
-        } else {
-            Ok(gl.get_active_uniform(program_id.get(), index))
-        };
-        chan.send(result).unwrap();
-    }
-
     fn finish(gl: &gl::Gl, chan: &WebGLSender<()>) {
         gl.finish();
         chan.send(()).unwrap();
@@ -1121,17 +1110,14 @@ impl WebGLImpl {
         chan.send(parameter).unwrap();
     }
 
-    fn uniform_location(gl: &gl::Gl,
-                        program_id: WebGLProgramId,
-                        name: &str,
-                        chan: &WebGLSender<Option<i32>>) {
-        let location = gl.get_uniform_location(program_id.get(), name);
-        let location = if location == -1 {
-            None
-        } else {
-            Some(location)
-        };
-
+    fn uniform_location(
+        gl: &gl::Gl,
+        program_id: WebGLProgramId,
+        name: &str,
+        chan: &WebGLSender<i32>,
+    ) {
+        let location = gl.get_uniform_location(program_id.get(), &to_name_in_compiled_shader(name));
+        assert!(location >= 0);
         chan.send(location).unwrap();
     }
 
@@ -1244,3 +1230,39 @@ impl WebGLImpl {
         gl.compile_shader(shader_id.get());
     }
 }
+
+/// ANGLE adds a `_u` prefix to variable names:
+///
+/// https://chromium.googlesource.com/angle/angle/+/855d964bd0d05f6b2cb303f625506cf53d37e94f
+///
+/// To avoid hard-coding this we would need to use the `sh::GetAttributes` and `sh::GetUniforms`
+/// API to look up the `x.name` and `x.mappedName` members.
+const ANGLE_NAME_PREFIX: &'static str = "_u";
+
+fn to_name_in_compiled_shader(s: &str) -> String {
+    map_dot_separated(s, |s, mapped| {
+        mapped.push_str(ANGLE_NAME_PREFIX);
+        mapped.push_str(s);
+    })
+}
+
+fn from_name_in_compiled_shader(s: &str) -> String {
+    map_dot_separated(s, |s, mapped| {
+        mapped.push_str(if s.starts_with(ANGLE_NAME_PREFIX) {
+            &s[ANGLE_NAME_PREFIX.len()..]
+        } else {
+            s
+        })
+    })
+}
+
+fn map_dot_separated<F: Fn(&str, &mut String)>(s: &str, f: F) -> String {
+    let mut iter = s.split('.');
+    let mut mapped = String::new();
+    f(iter.next().unwrap(), &mut mapped);
+    for s in iter {
+        mapped.push('.');
+        f(s, &mut mapped);
+    }
+    mapped
+}
diff --git a/components/canvas_traits/webgl.rs b/components/canvas_traits/webgl.rs
index 793f687698b..e4fc9d0d739 100644
--- a/components/canvas_traits/webgl.rs
+++ b/components/canvas_traits/webgl.rs
@@ -6,6 +6,7 @@ use euclid::Size2D;
 use gleam::gl;
 use offscreen_gl_context::{GLContextAttributes, GLLimits};
 use serde_bytes::ByteBuf;
+use std::borrow::Cow;
 use std::num::NonZeroU32;
 use webrender_api::{DocumentId, ImageKey, PipelineId};
 
@@ -207,9 +208,7 @@ pub enum WebGLCommand {
     FramebufferTexture2D(u32, u32, u32, Option<WebGLTextureId>, i32),
     GetExtensions(WebGLSender<String>),
     GetShaderPrecisionFormat(u32, u32, WebGLSender<(i32, i32, i32)>),
-    GetActiveAttrib(WebGLProgramId, u32, WebGLSender<WebGLResult<(i32, u32, String)>>),
-    GetActiveUniform(WebGLProgramId, u32, WebGLSender<WebGLResult<(i32, u32, String)>>),
-    GetUniformLocation(WebGLProgramId, String, WebGLSender<Option<i32>>),
+    GetUniformLocation(WebGLProgramId, String, WebGLSender<i32>),
     GetShaderInfoLog(WebGLShaderId, WebGLSender<String>),
     GetProgramInfoLog(WebGLProgramId, WebGLSender<String>),
     GetFramebufferAttachmentParameter(u32, u32, u32, WebGLSender<i32>),
@@ -246,9 +245,9 @@ pub enum WebGLCommand {
     Uniform4fv(i32, Vec<f32>),
     Uniform4i(i32, i32, i32, i32, i32),
     Uniform4iv(i32, Vec<i32>),
-    UniformMatrix2fv(i32, bool, Vec<f32>),
-    UniformMatrix3fv(i32, bool, Vec<f32>),
-    UniformMatrix4fv(i32, bool, Vec<f32>),
+    UniformMatrix2fv(i32, Vec<f32>),
+    UniformMatrix3fv(i32, Vec<f32>),
+    UniformMatrix4fv(i32, Vec<f32>),
     UseProgram(Option<WebGLProgramId>),
     ValidateProgram(WebGLProgramId),
     VertexAttrib(u32, f32, f32, f32, f32),
@@ -425,6 +424,8 @@ pub struct ProgramLinkInfo {
     pub linked: bool,
     /// The list of active attributes.
     pub active_attribs: Box<[ActiveAttribInfo]>,
+    /// The list of active uniforms.
+    pub active_uniforms: Box<[ActiveUniformInfo]>,
 }
 
 /// Description of a single active attribute.
@@ -440,6 +441,29 @@ pub struct ActiveAttribInfo {
     pub location: i32,
 }
 
+/// Description of a single active uniform.
+#[derive(Clone, Deserialize, MallocSizeOf, Serialize)]
+pub struct ActiveUniformInfo {
+    /// The base name of the uniform.
+    pub base_name: Box<str>,
+    /// The size of the uniform, if it is an array.
+    pub size: Option<i32>,
+    /// The type of the uniform.
+    pub type_: u32,
+}
+
+impl ActiveUniformInfo {
+    pub fn name(&self) -> Cow<str> {
+        if self.size.is_some() {
+            let mut name = String::from(&*self.base_name);
+            name.push_str("[0]");
+            Cow::Owned(name)
+        } else {
+            Cow::Borrowed(&self.base_name)
+        }
+    }
+}
+
 macro_rules! parameters {
     ($name:ident { $(
         $variant:ident($kind:ident { $(
@@ -578,39 +602,3 @@ parameters! {
         }),
     }
 }
-
-/// ANGLE adds a `_u` prefix to variable names:
-///
-/// https://chromium.googlesource.com/angle/angle/+/855d964bd0d05f6b2cb303f625506cf53d37e94f
-///
-/// To avoid hard-coding this we would need to use the `sh::GetAttributes` and `sh::GetUniforms`
-/// API to look up the `x.name` and `x.mappedName` members.
-const ANGLE_NAME_PREFIX: &'static str = "_u";
-
-pub fn to_name_in_compiled_shader(s: &str) -> String {
-    map_dot_separated(s, |s, mapped| {
-        mapped.push_str(ANGLE_NAME_PREFIX);
-        mapped.push_str(s);
-    })
-}
-
-pub fn from_name_in_compiled_shader(s: &str) -> String {
-    map_dot_separated(s, |s, mapped| {
-        mapped.push_str(if s.starts_with(ANGLE_NAME_PREFIX) {
-            &s[ANGLE_NAME_PREFIX.len()..]
-        } else {
-            s
-        })
-    })
-}
-
-fn map_dot_separated<F: Fn(&str, &mut String)>(s: &str, f: F) -> String {
-    let mut iter = s.split('.');
-    let mut mapped = String::new();
-    f(iter.next().unwrap(), &mut mapped);
-    for s in iter {
-        mapped.push('.');
-        f(s, &mut mapped);
-    }
-    mapped
-}
diff --git a/components/script/dom/bindings/trace.rs b/components/script/dom/bindings/trace.rs
index 06892ec8478..74071e3fda2 100644
--- a/components/script/dom/bindings/trace.rs
+++ b/components/script/dom/bindings/trace.rs
@@ -32,10 +32,11 @@
 use app_units::Au;
 use canvas_traits::canvas::{CanvasGradientStop, CanvasId, LinearGradientStyle, RadialGradientStyle};
 use canvas_traits::canvas::{CompositionOrBlending, LineCapStyle, LineJoinStyle, RepetitionStyle};
-use canvas_traits::webgl::{ActiveAttribInfo, WebGLBufferId, WebGLFramebufferId, WebGLProgramId, WebGLRenderbufferId};
-use canvas_traits::webgl::{WebGLChan, WebGLContextShareMode, WebGLError, WebGLPipeline, WebGLMsgSender};
-use canvas_traits::webgl::{WebGLReceiver, WebGLSender, WebGLShaderId, WebGLTextureId, WebGLVertexArrayId};
-use canvas_traits::webgl::{WebGLSLVersion, WebGLVersion};
+use canvas_traits::webgl::{ActiveAttribInfo, ActiveUniformInfo, WebGLBufferId, WebGLChan};
+use canvas_traits::webgl::{WebGLContextShareMode, WebGLError, WebGLFramebufferId, WebGLMsgSender};
+use canvas_traits::webgl::{WebGLPipeline, WebGLProgramId, WebGLReceiver, WebGLRenderbufferId};
+use canvas_traits::webgl::{WebGLSLVersion, WebGLSender, WebGLShaderId, WebGLTextureId};
+use canvas_traits::webgl::{WebGLVersion, WebGLVertexArrayId};
 use cssparser::RGBA;
 use devtools_traits::{CSSError, TimelineMarkerType, WorkerId};
 use dom::abstractworker::SharedRt;
@@ -343,6 +344,7 @@ unsafe impl<A: JSTraceable, B: JSTraceable, C: JSTraceable> JSTraceable for (A,
 }
 
 unsafe_no_jsmanaged_fields!(ActiveAttribInfo);
+unsafe_no_jsmanaged_fields!(ActiveUniformInfo);
 unsafe_no_jsmanaged_fields!(bool, f32, f64, String, AtomicBool, AtomicUsize, Uuid, char);
 unsafe_no_jsmanaged_fields!(usize, u8, u16, u32, u64);
 unsafe_no_jsmanaged_fields!(isize, i8, i16, i32, i64);
diff --git a/components/script/dom/webglprogram.rs b/components/script/dom/webglprogram.rs
index d5902e1afff..8a354ffe9f2 100644
--- a/components/script/dom/webglprogram.rs
+++ b/components/script/dom/webglprogram.rs
@@ -3,9 +3,8 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 // https://www.khronos.org/registry/webgl/specs/latest/1.0/webgl.idl
-use canvas_traits::webgl::{ActiveAttribInfo, WebGLCommand, WebGLError, WebGLMsgSender};
-use canvas_traits::webgl::{WebGLProgramId, WebGLResult, from_name_in_compiled_shader};
-use canvas_traits::webgl::{to_name_in_compiled_shader, webgl_channel};
+use canvas_traits::webgl::{ActiveAttribInfo, ActiveUniformInfo, WebGLCommand, WebGLError};
+use canvas_traits::webgl::{WebGLMsgSender, WebGLProgramId, WebGLResult, webgl_channel};
 use dom::bindings::cell::DomRefCell;
 use dom::bindings::codegen::Bindings::WebGLProgramBinding;
 use dom::bindings::codegen::Bindings::WebGLRenderingContextBinding::WebGLRenderingContextConstants as constants;
@@ -16,6 +15,7 @@ use dom::webglactiveinfo::WebGLActiveInfo;
 use dom::webglobject::WebGLObject;
 use dom::webglrenderingcontext::MAX_UNIFORM_AND_ATTRIBUTE_LEN;
 use dom::webglshader::WebGLShader;
+use dom::webgluniformlocation::WebGLUniformLocation;
 use dom::window::Window;
 use dom_struct::dom_struct;
 use fnv::FnvHashSet;
@@ -33,6 +33,7 @@ pub struct WebGLProgram {
     #[ignore_malloc_size_of = "Defined in ipc-channel"]
     renderer: WebGLMsgSender,
     active_attribs: DomRefCell<Box<[ActiveAttribInfo]>>,
+    active_uniforms: DomRefCell<Box<[ActiveUniformInfo]>>,
 }
 
 impl WebGLProgram {
@@ -49,6 +50,7 @@ impl WebGLProgram {
             vertex_shader: Default::default(),
             renderer: renderer,
             active_attribs: DomRefCell::new(vec![].into()),
+            active_uniforms: DomRefCell::new(vec![].into()),
         }
     }
 
@@ -123,20 +125,30 @@ impl WebGLProgram {
         self.renderer.send(WebGLCommand::LinkProgram(self.id, sender)).unwrap();
         let link_info = receiver.recv().unwrap();
 
-        // https://www.khronos.org/registry/webgl/specs/latest/1.0/#6.31
-        let mut used_locs = FnvHashSet::default();
-        for active_attrib in &*link_info.active_attribs {
-            if active_attrib.location == -1 {
-                continue;
+        {
+            let mut used_locs = FnvHashSet::default();
+            let mut used_names = FnvHashSet::default();
+            for active_attrib in &*link_info.active_attribs {
+                if active_attrib.location == -1 {
+                    continue;
+                }
+                let columns = match active_attrib.type_ {
+                    constants::FLOAT_MAT2 => 2,
+                    constants::FLOAT_MAT3 => 3,
+                    constants::FLOAT_MAT4 => 4,
+                    _ => 1,
+                };
+                assert!(used_names.insert(&*active_attrib.name));
+                for column in 0..columns {
+                    // https://www.khronos.org/registry/webgl/specs/latest/1.0/#6.31
+                    if !used_locs.insert(active_attrib.location as u32 + column) {
+                        return Ok(());
+                    }
+                }
             }
-            let columns = match active_attrib.type_ {
-                constants::FLOAT_MAT2 => 2,
-                constants::FLOAT_MAT3 => 3,
-                constants::FLOAT_MAT4 => 4,
-                _ => 1,
-            };
-            for column in 0..columns {
-                if !used_locs.insert(active_attrib.location as u32 + column) {
+            for active_uniform in &*link_info.active_uniforms {
+                // https://www.khronos.org/registry/webgl/specs/latest/1.0/#6.41
+                if !used_names.insert(&*active_uniform.base_name) {
                     return Ok(());
                 }
             }
@@ -144,6 +156,7 @@ impl WebGLProgram {
 
         self.linked.set(link_info.linked);
         *self.active_attribs.borrow_mut() = link_info.active_attribs;
+        *self.active_uniforms.borrow_mut() = link_info.active_uniforms;
         Ok(())
     }
 
@@ -151,6 +164,10 @@ impl WebGLProgram {
         Ref::map(self.active_attribs.borrow(), |attribs| &**attribs)
     }
 
+    pub fn active_uniforms(&self) -> Ref<[ActiveUniformInfo]> {
+        Ref::map(self.active_uniforms.borrow(), |uniforms| &**uniforms)
+    }
+
     /// glValidateProgram
     pub fn validate(&self) -> WebGLResult<()> {
         if self.is_deleted() {
@@ -232,10 +249,8 @@ impl WebGLProgram {
             return Err(WebGLError::InvalidOperation);
         }
 
-        let name = to_name_in_compiled_shader(&name);
-
         self.renderer
-            .send(WebGLCommand::BindAttribLocation(self.id, index, name))
+            .send(WebGLCommand::BindAttribLocation(self.id, index, name.into()))
             .unwrap();
         Ok(())
     }
@@ -244,15 +259,14 @@ impl WebGLProgram {
         if self.is_deleted() {
             return Err(WebGLError::InvalidValue);
         }
-        let (sender, receiver) = webgl_channel().unwrap();
-        self.renderer
-            .send(WebGLCommand::GetActiveUniform(self.id, index, sender))
-            .unwrap();
-
-        receiver.recv().unwrap().map(|(size, ty, name)| {
-            let name = DOMString::from(from_name_in_compiled_shader(&name));
-            WebGLActiveInfo::new(self.global().as_window(), size, ty, name)
-        })
+        let uniforms = self.active_uniforms.borrow();
+        let data = uniforms.get(index as usize).ok_or(WebGLError::InvalidValue)?;
+        Ok(WebGLActiveInfo::new(
+            self.global().as_window(),
+            data.size.unwrap_or(1),
+            data.type_,
+            data.name().into(),
+        ))
     }
 
     /// glGetActiveAttrib
@@ -298,7 +312,10 @@ impl WebGLProgram {
     }
 
     /// glGetUniformLocation
-    pub fn get_uniform_location(&self, name: DOMString) -> WebGLResult<Option<i32>> {
+    pub fn get_uniform_location(
+        &self,
+        name: DOMString,
+    ) -> WebGLResult<Option<DomRoot<WebGLUniformLocation>>> {
         if !self.is_linked() || self.is_deleted() {
             return Err(WebGLError::InvalidOperation);
         }
@@ -307,17 +324,37 @@ impl WebGLProgram {
         }
 
         // Check if the name is reserved
-        if name.starts_with("webgl") || name.starts_with("_webgl_") {
+        if name.starts_with("gl_") {
             return Ok(None);
         }
 
-        let name = to_name_in_compiled_shader(&name);
+        // https://www.khronos.org/registry/webgl/specs/latest/1.0/#GLSL_CONSTRUCTS
+        if name.starts_with("webgl_") || name.starts_with("_webgl_") {
+            return Ok(None);
+        }
+
+        let (size, type_) = {
+            let (base_name, array_index) = match parse_uniform_name(&name) {
+                Some((name, index)) if index.map_or(true, |i| i >= 0) => (name, index),
+                _ => return Ok(None),
+            };
+
+            let uniforms = self.active_uniforms.borrow();
+            match uniforms.iter().find(|attrib| &*attrib.base_name == base_name) {
+                Some(uniform) if array_index.is_none() || array_index < uniform.size => {
+                    (uniform.size.map(|size| size - array_index.unwrap_or_default()), uniform.type_)
+                },
+                _ => return Ok(None),
+            }
+        };
 
         let (sender, receiver) = webgl_channel().unwrap();
         self.renderer
-            .send(WebGLCommand::GetUniformLocation(self.id, name, sender))
+            .send(WebGLCommand::GetUniformLocation(self.id, name.into(), sender))
             .unwrap();
-        Ok(receiver.recv().unwrap())
+        let location = receiver.recv().unwrap();
+
+        Ok(Some(WebGLUniformLocation::new(self.global().as_window(), location, self.id, size, type_)))
     }
 
     /// glGetProgramInfoLog
@@ -358,3 +395,13 @@ impl Drop for WebGLProgram {
         self.delete();
     }
 }
+
+
+fn parse_uniform_name(name: &str) -> Option<(&str, Option<i32>)> {
+    if !name.ends_with(']') {
+        return Some((name, None));
+    }
+    let bracket_pos = name[..name.len() - 1].rfind('[')?;
+    let index = name[(bracket_pos + 1)..(name.len() - 1)].parse::<i32>().ok()?;
+    Some((&name[..bracket_pos], Some(index)))
+}
diff --git a/components/script/dom/webglrenderingcontext.rs b/components/script/dom/webglrenderingcontext.rs
index 34d085d7f6b..317a51d0cbf 100644
--- a/components/script/dom/webglrenderingcontext.rs
+++ b/components/script/dom/webglrenderingcontext.rs
@@ -425,6 +425,21 @@ impl WebGLRenderingContext {
         }
     }
 
+    fn with_location<F>(&self, location: Option<&WebGLUniformLocation>, f: F)
+    where
+        F: FnOnce(&WebGLUniformLocation) -> WebGLResult<()>,
+    {
+        let location = match location {
+            Some(loc) => loc,
+            None => return,
+        };
+        match self.current_program.get() {
+            Some(ref program) if program.id() == location.program_id() => {}
+            _ => return self.webgl_error(InvalidOperation),
+        }
+        handle_potential_webgl_error!(self, f(location));
+    }
+
     fn tex_parameter(&self, target: u32, name: u32, value: TexParameterValue) {
         let texture = match target {
             constants::TEXTURE_2D |
@@ -528,38 +543,6 @@ impl WebGLRenderingContext {
         }
     }
 
-    // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.10
-    // https://www.khronos.org/opengles/sdk/docs/man/xhtml/glUniform.xml
-    // https://www.khronos.org/registry/gles/specs/2.0/es_full_spec_2.0.25.pdf#nameddest=section-2.10.4
-    fn validate_uniform_parameters<T>(&self,
-                                      uniform: Option<&WebGLUniformLocation>,
-                                      uniform_type: UniformSetterType,
-                                      data: &[T]) -> bool {
-        let uniform = match uniform {
-            Some(uniform) => uniform,
-            None => return false,
-        };
-
-        let program = self.current_program.get();
-        match program {
-            Some(ref program) if program.id() == uniform.program_id() => {},
-            _ => {
-                self.webgl_error(InvalidOperation);
-                return false;
-            },
-        };
-
-        // TODO(emilio): Get more complex uniform info from ANGLE, and use it to
-        // properly validate that the uniform setter type is compatible with the
-        // uniform type, and that the uniform size matches.
-        if data.len() % uniform_type.element_count() != 0 {
-            self.webgl_error(InvalidOperation);
-            return false;
-        }
-
-        true
-    }
-
     // https://en.wikipedia.org/wiki/Relative_luminance
     #[inline]
     fn luminance(r: u8, g: u8, b: u8) -> u8 {
@@ -2693,12 +2676,7 @@ impl WebGLRenderingContextMethods for WebGLRenderingContext {
                 Int32Value(program.attached_shaders().map(|shaders| shaders.len() as i32).unwrap_or(0))
             }
             constants::ACTIVE_ATTRIBUTES => Int32Value(program.active_attribs().len() as i32),
-            constants::ACTIVE_UNIFORMS => {
-                // FIXME(nox): We'll need to cache that on the DOM side at some point.
-                let (sender, receiver) = webgl_channel().unwrap();
-                self.send_command(WebGLCommand::GetProgramActiveUniforms(program.id(), sender));
-                Int32Value(receiver.recv().unwrap())
-            }
+            constants::ACTIVE_UNIFORMS => Int32Value(program.active_uniforms().len() as i32),
             _ => {
                 self.webgl_error(InvalidEnum);
                 NullValue()
@@ -2767,9 +2745,7 @@ impl WebGLRenderingContextMethods for WebGLRenderingContext {
         program: &WebGLProgram,
         name: DOMString,
     ) -> Option<DomRoot<WebGLUniformLocation>> {
-        handle_potential_webgl_error!(self, program.get_uniform_location(name), None).map(|location| {
-            WebGLUniformLocation::new(self.global().as_window(), location, program.id())
-        })
+        handle_potential_webgl_error!(self, program.get_uniform_location(name), None)
     }
 
     #[allow(unsafe_code)]
@@ -3171,75 +3147,145 @@ impl WebGLRenderingContextMethods for WebGLRenderingContext {
     }
 
     // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.10
-    fn Uniform1f(&self,
-                  location: Option<&WebGLUniformLocation>,
-                  val: f32) {
-        if self.validate_uniform_parameters(location, UniformSetterType::Float, &[val]) {
-            self.send_command(WebGLCommand::Uniform1f(location.unwrap().id(), val))
-        }
+    fn Uniform1f(
+        &self,
+        location: Option<&WebGLUniformLocation>,
+        val: f32,
+    ) {
+        self.with_location(location, |location| {
+            match location.type_() {
+                constants::BOOL | constants::FLOAT => {}
+                _ => return Err(InvalidOperation),
+            }
+            self.send_command(WebGLCommand::Uniform1f(location.id(), val));
+            Ok(())
+        });
     }
 
     // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.10
-    fn Uniform1i(&self,
-                  location: Option<&WebGLUniformLocation>,
-                  val: i32) {
-        if self.validate_uniform_parameters(location, UniformSetterType::Int, &[val]) {
-            self.send_command(WebGLCommand::Uniform1i(location.unwrap().id(), val))
-        }
+    fn Uniform1i(
+        &self,
+        location: Option<&WebGLUniformLocation>,
+        val: i32,
+    ) {
+        self.with_location(location, |location| {
+            match location.type_() {
+                constants::BOOL | constants::INT => {}
+                constants::SAMPLER_2D | constants::SAMPLER_CUBE => {
+                    if val < 0 || val as u32 >= self.limits.max_combined_texture_image_units {
+                        return Err(InvalidValue);
+                    }
+                }
+                _ => return Err(InvalidOperation),
+            }
+            self.send_command(WebGLCommand::Uniform1i(location.id(), val));
+            Ok(())
+        });
     }
 
     // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.10
     fn Uniform1iv(
         &self,
         location: Option<&WebGLUniformLocation>,
-        v: Int32ArrayOrLongSequence,
+        val: Int32ArrayOrLongSequence,
     ) {
-        let v = match v {
-            Int32ArrayOrLongSequence::Int32Array(v) => v.to_vec(),
-            Int32ArrayOrLongSequence::LongSequence(v) => v,
-        };
-        if self.validate_uniform_parameters(location, UniformSetterType::Int, &v) {
-            self.send_command(WebGLCommand::Uniform1iv(location.unwrap().id(), v))
-        }
+        self.with_location(location, |location| {
+            match location.type_() {
+                constants::BOOL | constants::INT | constants::SAMPLER_2D | constants::SAMPLER_CUBE => {}
+                _ => return Err(InvalidOperation),
+            }
+            let val = match val {
+                Int32ArrayOrLongSequence::Int32Array(v) => v.to_vec(),
+                Int32ArrayOrLongSequence::LongSequence(v) => v,
+            };
+            if val.is_empty() {
+                return Err(InvalidValue);
+            }
+            if location.size().is_none() && val.len() != 1 {
+                return Err(InvalidOperation);
+            }
+            match location.type_() {
+                constants::SAMPLER_2D | constants::SAMPLER_CUBE => {
+                    for &v in val.iter().take(cmp::min(location.size().unwrap_or(1) as usize, val.len())) {
+                        if v < 0 || v as u32 >= self.limits.max_combined_texture_image_units {
+                            return Err(InvalidValue);
+                        }
+                    }
+                }
+                _ => {}
+            }
+            self.send_command(WebGLCommand::Uniform1iv(location.id(), val));
+            Ok(())
+        });
     }
 
     // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.10
     fn Uniform1fv(
         &self,
         location: Option<&WebGLUniformLocation>,
-        v: Float32ArrayOrUnrestrictedFloatSequence,
+        val: Float32ArrayOrUnrestrictedFloatSequence,
     ) {
-        let v = match v {
-            Float32ArrayOrUnrestrictedFloatSequence::Float32Array(v) => v.to_vec(),
-            Float32ArrayOrUnrestrictedFloatSequence::UnrestrictedFloatSequence(v) => v,
-        };
-        if self.validate_uniform_parameters(location, UniformSetterType::Float, &v) {
-            self.send_command(WebGLCommand::Uniform1fv(location.unwrap().id(), v));
-        }
+        self.with_location(location, |location| {
+            match location.type_() {
+                constants::BOOL | constants::FLOAT => {}
+                _ => return Err(InvalidOperation),
+            }
+            let val = match val {
+                Float32ArrayOrUnrestrictedFloatSequence::Float32Array(v) => v.to_vec(),
+                Float32ArrayOrUnrestrictedFloatSequence::UnrestrictedFloatSequence(v) => v,
+            };
+            if val.is_empty() {
+                return Err(InvalidValue);
+            }
+            if location.size().is_none() && val.len() != 1 {
+                return Err(InvalidOperation);
+            }
+            self.send_command(WebGLCommand::Uniform1fv(location.id(), val));
+            Ok(())
+        });
     }
 
     // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.10
-    fn Uniform2f(&self,
-                  location: Option<&WebGLUniformLocation>,
-                  x: f32, y: f32) {
-        if self.validate_uniform_parameters(location, UniformSetterType::FloatVec2, &[x, y]) {
-            self.send_command(WebGLCommand::Uniform2f(location.unwrap().id(), x, y));
-        }
+    fn Uniform2f(
+        &self,
+        location: Option<&WebGLUniformLocation>,
+        x: f32,
+        y: f32,
+    ) {
+        self.with_location(location, |location| {
+            match location.type_() {
+                constants::BOOL_VEC2 | constants::FLOAT_VEC2 => {}
+                _ => return Err(InvalidOperation),
+            }
+            self.send_command(WebGLCommand::Uniform2f(location.id(), x, y));
+            Ok(())
+        });
     }
 
     // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.10
     fn Uniform2fv(
         &self,
         location: Option<&WebGLUniformLocation>,
-        v: Float32ArrayOrUnrestrictedFloatSequence,
+        val: Float32ArrayOrUnrestrictedFloatSequence,
     ) {
-        let v = match v {
-            Float32ArrayOrUnrestrictedFloatSequence::Float32Array(v) => v.to_vec(),
-            Float32ArrayOrUnrestrictedFloatSequence::UnrestrictedFloatSequence(v) => v,
-        };
-        if self.validate_uniform_parameters(location, UniformSetterType::FloatVec2, &v) {
-            self.send_command(WebGLCommand::Uniform2fv(location.unwrap().id(), v));
-        }
+        self.with_location(location, |location| {
+            match location.type_() {
+                constants::BOOL_VEC2 | constants::FLOAT_VEC2 => {}
+                _ => return Err(InvalidOperation),
+            }
+            let val = match val {
+                Float32ArrayOrUnrestrictedFloatSequence::Float32Array(v) => v.to_vec(),
+                Float32ArrayOrUnrestrictedFloatSequence::UnrestrictedFloatSequence(v) => v,
+            };
+            if val.len() < 2 || val.len() % 2 != 0 {
+                return Err(InvalidValue);
+            }
+            if location.size().is_none() && val.len() != 2 {
+                return Err(InvalidOperation);
+            }
+            self.send_command(WebGLCommand::Uniform2fv(location.id(), val));
+            Ok(())
+        });
     }
 
     // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.10
@@ -3249,26 +3295,40 @@ impl WebGLRenderingContextMethods for WebGLRenderingContext {
         x: i32,
         y: i32,
     ) {
-        if self.validate_uniform_parameters(location,
-                                            UniformSetterType::IntVec2,
-                                            &[x, y]) {
-            self.send_command(WebGLCommand::Uniform2i(location.unwrap().id(), x, y));
-        }
+        self.with_location(location, |location| {
+            match location.type_() {
+                constants::BOOL_VEC2 | constants::INT_VEC2 => {}
+                _ => return Err(InvalidOperation),
+            }
+            self.send_command(WebGLCommand::Uniform2i(location.id(), x, y));
+            Ok(())
+        });
     }
 
     // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.10
     fn Uniform2iv(
         &self,
         location: Option<&WebGLUniformLocation>,
-        v: Int32ArrayOrLongSequence,
+        val: Int32ArrayOrLongSequence,
     ) {
-        let v = match v {
-            Int32ArrayOrLongSequence::Int32Array(v) => v.to_vec(),
-            Int32ArrayOrLongSequence::LongSequence(v) => v,
-        };
-        if self.validate_uniform_parameters(location, UniformSetterType::IntVec2, &v) {
-            self.send_command(WebGLCommand::Uniform2iv(location.unwrap().id(), v));
-        }
+        self.with_location(location, |location| {
+            match location.type_() {
+                constants::BOOL_VEC2 | constants::INT_VEC2 => {}
+                _ => return Err(InvalidOperation),
+            }
+            let val = match val {
+                Int32ArrayOrLongSequence::Int32Array(v) => v.to_vec(),
+                Int32ArrayOrLongSequence::LongSequence(v) => v,
+            };
+            if val.len() < 2 || val.len() % 2 != 0 {
+                return Err(InvalidValue);
+            }
+            if location.size().is_none() && val.len() != 2 {
+                return Err(InvalidOperation);
+            }
+            self.send_command(WebGLCommand::Uniform2iv(location.id(), val));
+            Ok(())
+        });
     }
 
     // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.10
@@ -3279,52 +3339,84 @@ impl WebGLRenderingContextMethods for WebGLRenderingContext {
         y: f32,
         z: f32,
     ) {
-        if self.validate_uniform_parameters(location,
-                                            UniformSetterType::FloatVec3,
-                                            &[x, y, z]) {
-            self.send_command(WebGLCommand::Uniform3f(location.unwrap().id(), x, y, z));
-        }
+        self.with_location(location, |location| {
+            match location.type_() {
+                constants::BOOL_VEC3 | constants::FLOAT_VEC3 => {}
+                _ => return Err(InvalidOperation),
+            }
+            self.send_command(WebGLCommand::Uniform3f(location.id(), x, y, z));
+            Ok(())
+        });
     }
 
     // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.10
     fn Uniform3fv(
         &self,
         location: Option<&WebGLUniformLocation>,
-        v: Float32ArrayOrUnrestrictedFloatSequence,
+        val: Float32ArrayOrUnrestrictedFloatSequence,
     ) {
-        let v = match v {
-            Float32ArrayOrUnrestrictedFloatSequence::Float32Array(v) => v.to_vec(),
-            Float32ArrayOrUnrestrictedFloatSequence::UnrestrictedFloatSequence(v) => v,
-        };
-        if self.validate_uniform_parameters(location, UniformSetterType::FloatVec3, &v) {
-            self.send_command(WebGLCommand::Uniform3fv(location.unwrap().id(), v))
-        }
+        self.with_location(location, |location| {
+            match location.type_() {
+                constants::BOOL_VEC3 | constants::FLOAT_VEC3 => {}
+                _ => return Err(InvalidOperation),
+            }
+            let val = match val {
+                Float32ArrayOrUnrestrictedFloatSequence::Float32Array(v) => v.to_vec(),
+                Float32ArrayOrUnrestrictedFloatSequence::UnrestrictedFloatSequence(v) => v,
+            };
+            if val.len() < 3 || val.len() % 3 != 0 {
+                return Err(InvalidValue);
+            }
+            if location.size().is_none() && val.len() != 3 {
+                return Err(InvalidOperation);
+            }
+            self.send_command(WebGLCommand::Uniform3fv(location.id(), val));
+            Ok(())
+        });
     }
 
     // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.10
-    fn Uniform3i(&self,
-                  location: Option<&WebGLUniformLocation>,
-                  x: i32, y: i32, z: i32) {
-        if self.validate_uniform_parameters(location,
-                                            UniformSetterType::IntVec3,
-                                            &[x, y, z]) {
-            self.send_command(WebGLCommand::Uniform3i(location.unwrap().id(), x, y, z))
-        }
+    fn Uniform3i(
+        &self,
+        location: Option<&WebGLUniformLocation>,
+        x: i32,
+        y: i32,
+        z: i32,
+    ) {
+        self.with_location(location, |location| {
+            match location.type_() {
+                constants::BOOL_VEC3 | constants::INT_VEC3 => {}
+                _ => return Err(InvalidOperation),
+            }
+            self.send_command(WebGLCommand::Uniform3i(location.id(), x, y, z));
+            Ok(())
+        });
     }
 
     // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.10
     fn Uniform3iv(
         &self,
         location: Option<&WebGLUniformLocation>,
-        v: Int32ArrayOrLongSequence,
+        val: Int32ArrayOrLongSequence,
     ) {
-        let v = match v {
-            Int32ArrayOrLongSequence::Int32Array(v) => v.to_vec(),
-            Int32ArrayOrLongSequence::LongSequence(v) => v,
-        };
-        if self.validate_uniform_parameters(location, UniformSetterType::IntVec3, &v) {
-            self.send_command(WebGLCommand::Uniform3iv(location.unwrap().id(), v))
-        }
+        self.with_location(location, |location| {
+            match location.type_() {
+                constants::BOOL_VEC3 | constants::INT_VEC3 => {}
+                _ => return Err(InvalidOperation),
+            }
+            let val = match val {
+                Int32ArrayOrLongSequence::Int32Array(v) => v.to_vec(),
+                Int32ArrayOrLongSequence::LongSequence(v) => v,
+            };
+            if val.len() < 3 || val.len() % 3 != 0 {
+                return Err(InvalidValue);
+            }
+            if location.size().is_none() && val.len() != 3 {
+                return Err(InvalidOperation);
+            }
+            self.send_command(WebGLCommand::Uniform3iv(location.id(), val));
+            Ok(())
+        });
     }
 
     // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.10
@@ -3336,11 +3428,14 @@ impl WebGLRenderingContextMethods for WebGLRenderingContext {
         z: i32,
         w: i32,
     ) {
-        if self.validate_uniform_parameters(location,
-                                            UniformSetterType::IntVec4,
-                                            &[x, y, z, w]) {
-            self.send_command(WebGLCommand::Uniform4i(location.unwrap().id(), x, y, z, w))
-        }
+        self.with_location(location, |location| {
+            match location.type_() {
+                constants::BOOL_VEC4 | constants::INT_VEC4 => {}
+                _ => return Err(InvalidOperation),
+            }
+            self.send_command(WebGLCommand::Uniform4i(location.id(), x, y, z, w));
+            Ok(())
+        });
     }
 
 
@@ -3348,15 +3443,26 @@ impl WebGLRenderingContextMethods for WebGLRenderingContext {
     fn Uniform4iv(
         &self,
         location: Option<&WebGLUniformLocation>,
-        v: Int32ArrayOrLongSequence,
+        val: Int32ArrayOrLongSequence,
     ) {
-        let v = match v {
-            Int32ArrayOrLongSequence::Int32Array(v) => v.to_vec(),
-            Int32ArrayOrLongSequence::LongSequence(v) => v,
-        };
-        if self.validate_uniform_parameters(location, UniformSetterType::IntVec4, &v) {
-            self.send_command(WebGLCommand::Uniform4iv(location.unwrap().id(), v))
-        }
+        self.with_location(location, |location| {
+            match location.type_() {
+                constants::BOOL_VEC4 | constants::INT_VEC4 => {}
+                _ => return Err(InvalidOperation),
+            }
+            let val = match val {
+                Int32ArrayOrLongSequence::Int32Array(v) => v.to_vec(),
+                Int32ArrayOrLongSequence::LongSequence(v) => v,
+            };
+            if val.len() < 4 || val.len() % 4 != 0 {
+                return Err(InvalidValue);
+            }
+            if location.size().is_none() && val.len() != 4 {
+                return Err(InvalidOperation);
+            }
+            self.send_command(WebGLCommand::Uniform4iv(location.id(), val));
+            Ok(())
+        });
     }
 
     // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.10
@@ -3368,26 +3474,40 @@ impl WebGLRenderingContextMethods for WebGLRenderingContext {
         z: f32,
         w: f32,
     ) {
-        if self.validate_uniform_parameters(location,
-                                            UniformSetterType::FloatVec4,
-                                            &[x, y, z, w]) {
-            self.send_command(WebGLCommand::Uniform4f(location.unwrap().id(), x, y, z, w))
-        }
+        self.with_location(location, |location| {
+            match location.type_() {
+                constants::BOOL_VEC4 | constants::FLOAT_VEC4 => {}
+                _ => return Err(InvalidOperation),
+            }
+            self.send_command(WebGLCommand::Uniform4f(location.id(), x, y, z, w));
+            Ok(())
+        });
     }
 
     // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.10
     fn Uniform4fv(
         &self,
         location: Option<&WebGLUniformLocation>,
-        v: Float32ArrayOrUnrestrictedFloatSequence,
+        val: Float32ArrayOrUnrestrictedFloatSequence,
     ) {
-        let v = match v {
-            Float32ArrayOrUnrestrictedFloatSequence::Float32Array(v) => v.to_vec(),
-            Float32ArrayOrUnrestrictedFloatSequence::UnrestrictedFloatSequence(v) => v,
-        };
-        if self.validate_uniform_parameters(location, UniformSetterType::FloatVec4, &v) {
-            self.send_command(WebGLCommand::Uniform4fv(location.unwrap().id(), v))
-        }
+        self.with_location(location, |location| {
+            match location.type_() {
+                constants::BOOL_VEC4 | constants::FLOAT_VEC4 => {}
+                _ => return Err(InvalidOperation),
+            }
+            let val = match val {
+                Float32ArrayOrUnrestrictedFloatSequence::Float32Array(v) => v.to_vec(),
+                Float32ArrayOrUnrestrictedFloatSequence::UnrestrictedFloatSequence(v) => v,
+            };
+            if val.len() < 4 || val.len() % 4 != 0 {
+                return Err(InvalidValue);
+            }
+            if location.size().is_none() && val.len() != 4 {
+                return Err(InvalidOperation);
+            }
+            self.send_command(WebGLCommand::Uniform4fv(location.id(), val));
+            Ok(())
+        });
     }
 
     // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.10
@@ -3395,15 +3515,29 @@ impl WebGLRenderingContextMethods for WebGLRenderingContext {
         &self,
         location: Option<&WebGLUniformLocation>,
         transpose: bool,
-        v: Float32ArrayOrUnrestrictedFloatSequence,
+        val: Float32ArrayOrUnrestrictedFloatSequence,
     ) {
-        let v = match v {
-            Float32ArrayOrUnrestrictedFloatSequence::Float32Array(v) => v.to_vec(),
-            Float32ArrayOrUnrestrictedFloatSequence::UnrestrictedFloatSequence(v) => v,
-        };
-        if self.validate_uniform_parameters(location, UniformSetterType::FloatMat2, &v) {
-            self.send_command(WebGLCommand::UniformMatrix2fv(location.unwrap().id(), transpose, v));
-        }
+        self.with_location(location, |location| {
+            match location.type_() {
+                constants::FLOAT_MAT2 => {}
+                _ => return Err(InvalidOperation),
+            }
+            let val = match val {
+                Float32ArrayOrUnrestrictedFloatSequence::Float32Array(v) => v.to_vec(),
+                Float32ArrayOrUnrestrictedFloatSequence::UnrestrictedFloatSequence(v) => v,
+            };
+            if transpose {
+                return Err(InvalidValue);
+            }
+            if val.len() < 4 || val.len() % 4 != 0 {
+                return Err(InvalidValue);
+            }
+            if location.size().is_none() && val.len() != 4 {
+                return Err(InvalidOperation);
+            }
+            self.send_command(WebGLCommand::UniformMatrix2fv(location.id(), val));
+            Ok(())
+        });
     }
 
     // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.10
@@ -3411,15 +3545,29 @@ impl WebGLRenderingContextMethods for WebGLRenderingContext {
         &self,
         location: Option<&WebGLUniformLocation>,
         transpose: bool,
-        v: Float32ArrayOrUnrestrictedFloatSequence,
+        val: Float32ArrayOrUnrestrictedFloatSequence,
     ) {
-        let v = match v {
-            Float32ArrayOrUnrestrictedFloatSequence::Float32Array(v) => v.to_vec(),
-            Float32ArrayOrUnrestrictedFloatSequence::UnrestrictedFloatSequence(v) => v,
-        };
-        if self.validate_uniform_parameters(location, UniformSetterType::FloatMat3, &v) {
-            self.send_command(WebGLCommand::UniformMatrix3fv(location.unwrap().id(), transpose, v));
-        }
+        self.with_location(location, |location| {
+            match location.type_() {
+                constants::FLOAT_MAT3 => {}
+                _ => return Err(InvalidOperation),
+            }
+            let val = match val {
+                Float32ArrayOrUnrestrictedFloatSequence::Float32Array(v) => v.to_vec(),
+                Float32ArrayOrUnrestrictedFloatSequence::UnrestrictedFloatSequence(v) => v,
+            };
+            if transpose {
+                return Err(InvalidValue);
+            }
+            if val.len() < 9 || val.len() % 9 != 0 {
+                return Err(InvalidValue);
+            }
+            if location.size().is_none() && val.len() != 9 {
+                return Err(InvalidOperation);
+            }
+            self.send_command(WebGLCommand::UniformMatrix3fv(location.id(), val));
+            Ok(())
+        });
     }
 
     // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.10
@@ -3427,15 +3575,29 @@ impl WebGLRenderingContextMethods for WebGLRenderingContext {
         &self,
         location: Option<&WebGLUniformLocation>,
         transpose: bool,
-        v: Float32ArrayOrUnrestrictedFloatSequence,
+        val: Float32ArrayOrUnrestrictedFloatSequence,
     ) {
-        let v = match v {
-            Float32ArrayOrUnrestrictedFloatSequence::Float32Array(v) => v.to_vec(),
-            Float32ArrayOrUnrestrictedFloatSequence::UnrestrictedFloatSequence(v) => v,
-        };
-        if self.validate_uniform_parameters(location, UniformSetterType::FloatMat4, &v) {
-            self.send_command(WebGLCommand::UniformMatrix4fv(location.unwrap().id(), transpose, v));
-        }
+        self.with_location(location, |location| {
+            match location.type_() {
+                constants::FLOAT_MAT4 => {}
+                _ => return Err(InvalidOperation),
+            }
+            let val = match val {
+                Float32ArrayOrUnrestrictedFloatSequence::Float32Array(v) => v.to_vec(),
+                Float32ArrayOrUnrestrictedFloatSequence::UnrestrictedFloatSequence(v) => v,
+            };
+            if transpose {
+                return Err(InvalidValue);
+            }
+            if val.len() < 16 || val.len() % 16 != 0 {
+                return Err(InvalidValue);
+            }
+            if location.size().is_none() && val.len() != 16 {
+                return Err(InvalidOperation);
+            }
+            self.send_command(WebGLCommand::UniformMatrix4fv(location.id(), val));
+            Ok(())
+        });
     }
 
     // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.9
@@ -3937,39 +4099,6 @@ impl LayoutCanvasWebGLRenderingContextHelpers for LayoutDom<WebGLRenderingContex
     }
 }
 
-#[derive(Debug, PartialEq)]
-pub enum UniformSetterType {
-    Int,
-    IntVec2,
-    IntVec3,
-    IntVec4,
-    Float,
-    FloatVec2,
-    FloatVec3,
-    FloatVec4,
-    FloatMat2,
-    FloatMat3,
-    FloatMat4,
-}
-
-impl UniformSetterType {
-    pub fn element_count(&self) -> usize {
-        match *self {
-            UniformSetterType::Int => 1,
-            UniformSetterType::IntVec2 => 2,
-            UniformSetterType::IntVec3 => 3,
-            UniformSetterType::IntVec4 => 4,
-            UniformSetterType::Float => 1,
-            UniformSetterType::FloatVec2 => 2,
-            UniformSetterType::FloatVec3 => 3,
-            UniformSetterType::FloatVec4 => 4,
-            UniformSetterType::FloatMat2 => 4,
-            UniformSetterType::FloatMat3 => 9,
-            UniformSetterType::FloatMat4 => 16,
-        }
-    }
-}
-
 #[derive(JSTraceable, MallocSizeOf)]
 #[must_root]
 pub struct VertexAttribs {
diff --git a/components/script/dom/webgluniformlocation.rs b/components/script/dom/webgluniformlocation.rs
index 45662a446d3..db44ff9c969 100644
--- a/components/script/dom/webgluniformlocation.rs
+++ b/components/script/dom/webgluniformlocation.rs
@@ -15,26 +15,38 @@ pub struct WebGLUniformLocation {
     reflector_: Reflector,
     id: i32,
     program_id: WebGLProgramId,
+    size: Option<i32>,
+    type_: u32,
 }
 
 impl WebGLUniformLocation {
-    fn new_inherited(id: i32,
-                     program_id: WebGLProgramId)
-                     -> WebGLUniformLocation {
-        WebGLUniformLocation {
+    fn new_inherited(
+        id: i32,
+        program_id: WebGLProgramId,
+        size: Option<i32>,
+        type_: u32,
+    ) -> Self {
+        Self {
             reflector_: Reflector::new(),
-            id: id,
-            program_id: program_id,
+            id,
+            program_id,
+            size,
+            type_,
         }
     }
 
-    pub fn new(window: &Window,
-               id: i32,
-               program_id: WebGLProgramId)
-               -> DomRoot<WebGLUniformLocation> {
-        reflect_dom_object(Box::new(WebGLUniformLocation::new_inherited(id, program_id)),
-                           window,
-                           WebGLUniformLocationBinding::Wrap)
+    pub fn new(
+        window: &Window,
+        id: i32,
+        program_id: WebGLProgramId,
+        size: Option<i32>,
+        type_: u32,
+    ) -> DomRoot<Self> {
+        reflect_dom_object(
+            Box::new(Self::new_inherited(id, program_id, size, type_)),
+            window,
+            WebGLUniformLocationBinding::Wrap,
+        )
     }
 
     pub fn id(&self) -> i32 {
@@ -44,4 +56,12 @@ impl WebGLUniformLocation {
     pub fn program_id(&self) -> WebGLProgramId {
         self.program_id
     }
+
+    pub fn size(&self) -> Option<i32> {
+        self.size
+    }
+
+    pub fn type_(&self) -> u32 {
+        self.type_
+    }
 }
diff --git a/tests/wpt/mozilla/meta/webgl/conformance-1.0.3/conformance/misc/type-conversion-test.html.ini b/tests/wpt/mozilla/meta/webgl/conformance-1.0.3/conformance/misc/type-conversion-test.html.ini
index d25329622c1..b2775ef732b 100644
--- a/tests/wpt/mozilla/meta/webgl/conformance-1.0.3/conformance/misc/type-conversion-test.html.ini
+++ b/tests/wpt/mozilla/meta/webgl/conformance-1.0.3/conformance/misc/type-conversion-test.html.ini
@@ -1,3 +1,20 @@
 [type-conversion-test.html]
   type: testharness
-  expected: CRASH
+  [WebGL test #340: context.bufferData(context.ARRAY_BUFFER, argument, context.STATIC_DRAW) should be undefined. Threw exception TypeError: Not an ArrayBufferView]
+    expected: FAIL
+
+  [WebGL test #407: context.bufferData(context.ARRAY_BUFFER, argument, context.STATIC_DRAW) should be undefined. Threw exception TypeError: Not an ArrayBufferView]
+    expected: FAIL
+
+  [WebGL test #474: context.bufferData(context.ARRAY_BUFFER, argument, context.STATIC_DRAW) should be undefined. Threw exception TypeError: Not an ArrayBufferView]
+    expected: FAIL
+
+  [WebGL test #541: context.bufferData(context.ARRAY_BUFFER, argument, context.STATIC_DRAW) should be undefined. Threw exception TypeError: Not an ArrayBufferView]
+    expected: FAIL
+
+  [WebGL test #608: context.bufferData(context.ARRAY_BUFFER, argument, context.STATIC_DRAW) should be undefined. Threw exception TypeError: Not an ArrayBufferView]
+    expected: FAIL
+
+  [WebGL test #675: context.bufferData(context.ARRAY_BUFFER, argument, context.STATIC_DRAW) should be undefined. Threw exception TypeError: Not an ArrayBufferView]
+    expected: FAIL
+
diff --git a/tests/wpt/mozilla/meta/webgl/conformance-1.0.3/conformance/more/functions/uniformMatrixBadArgs.html.ini b/tests/wpt/mozilla/meta/webgl/conformance-1.0.3/conformance/more/functions/uniformMatrixBadArgs.html.ini
index 41408c4132b..a9c34e61d2d 100644
--- a/tests/wpt/mozilla/meta/webgl/conformance-1.0.3/conformance/more/functions/uniformMatrixBadArgs.html.ini
+++ b/tests/wpt/mozilla/meta/webgl/conformance-1.0.3/conformance/more/functions/uniformMatrixBadArgs.html.ini
@@ -1,3 +1,5 @@
 [uniformMatrixBadArgs.html]
   type: testharness
-  expected: CRASH
+  [WebGL test #0: testUniformf]
+    expected: FAIL
+
diff --git a/tests/wpt/mozilla/meta/webgl/conformance-1.0.3/conformance/more/functions/uniformfBadArgs.html.ini b/tests/wpt/mozilla/meta/webgl/conformance-1.0.3/conformance/more/functions/uniformfBadArgs.html.ini
deleted file mode 100644
index 0a2ca6a8c1c..00000000000
--- a/tests/wpt/mozilla/meta/webgl/conformance-1.0.3/conformance/more/functions/uniformfBadArgs.html.ini
+++ /dev/null
@@ -1,6 +0,0 @@
-[uniformfBadArgs.html]
-  type: testharness
-  expected: CRASH
-  [WebGL test #0: testUniformf]
-    expected: FAIL
-
diff --git a/tests/wpt/mozilla/meta/webgl/conformance-1.0.3/conformance/more/functions/uniformiBadArgs.html.ini b/tests/wpt/mozilla/meta/webgl/conformance-1.0.3/conformance/more/functions/uniformiBadArgs.html.ini
deleted file mode 100644
index 3b6cf9cd8bf..00000000000
--- a/tests/wpt/mozilla/meta/webgl/conformance-1.0.3/conformance/more/functions/uniformiBadArgs.html.ini
+++ /dev/null
@@ -1,6 +0,0 @@
-[uniformiBadArgs.html]
-  type: testharness
-  expected: CRASH
-  [WebGL test #0: testUniformf]
-    expected: FAIL
-
diff --git a/tests/wpt/mozilla/meta/webgl/conformance-1.0.3/conformance/uniforms/gl-uniform-arrays.html.ini b/tests/wpt/mozilla/meta/webgl/conformance-1.0.3/conformance/uniforms/gl-uniform-arrays.html.ini
index 65adb481bd3..d557119df79 100644
--- a/tests/wpt/mozilla/meta/webgl/conformance-1.0.3/conformance/uniforms/gl-uniform-arrays.html.ini
+++ b/tests/wpt/mozilla/meta/webgl/conformance-1.0.3/conformance/uniforms/gl-uniform-arrays.html.ini
@@ -1,3 +1,5 @@
 [gl-uniform-arrays.html]
-  type: testharness
-  disabled: flaky
+  expected: ERROR
+  [Overall test]
+    expected: NOTRUN
+
diff --git a/tests/wpt/mozilla/meta/webgl/conformance-1.0.3/conformance/uniforms/gl-uniformmatrix4fv.html.ini b/tests/wpt/mozilla/meta/webgl/conformance-1.0.3/conformance/uniforms/gl-uniformmatrix4fv.html.ini
deleted file mode 100644
index 6558b7e815f..00000000000
--- a/tests/wpt/mozilla/meta/webgl/conformance-1.0.3/conformance/uniforms/gl-uniformmatrix4fv.html.ini
+++ /dev/null
@@ -1,35 +0,0 @@
-[gl-uniformmatrix4fv.html]
-  type: testharness
-  [WebGL test #0: successfullyParsed should be true (of type boolean). Was undefined (of type undefined).]
-    expected: FAIL
-
-  [WebGL uniformMatrix Conformance Tests]
-    expected: FAIL
-
-  [WebGL test #0: getError expected: INVALID_VALUE. Was INVALID_OPERATION : should fail with insufficient array size for uniformMatrix2fv]
-    expected: FAIL
-
-  [WebGL test #2: getError expected: INVALID_VALUE. Was INVALID_OPERATION : should fail with more than 1 array size for uniformMatrix2fv]
-    expected: FAIL
-
-  [WebGL test #4: getError expected: INVALID_VALUE. Was NO_ERROR : uniformMatrix2fv should return INVALID_VALUE with transpose = true]
-    expected: FAIL
-
-  [WebGL test #5: getError expected: INVALID_VALUE. Was INVALID_OPERATION : should fail with insufficient array size for uniformMatrix3fv]
-    expected: FAIL
-
-  [WebGL test #7: getError expected: INVALID_VALUE. Was INVALID_OPERATION : should fail with more than 1 array size for uniformMatrix3fv]
-    expected: FAIL
-
-  [WebGL test #9: getError expected: INVALID_VALUE. Was NO_ERROR : uniformMatrix3fv should return INVALID_VALUE with transpose = true]
-    expected: FAIL
-
-  [WebGL test #10: getError expected: INVALID_VALUE. Was INVALID_OPERATION : should fail with insufficient array size for uniformMatrix4fv]
-    expected: FAIL
-
-  [WebGL test #12: getError expected: INVALID_VALUE. Was INVALID_OPERATION : should fail with more than 1 array size for uniformMatrix4fv]
-    expected: FAIL
-
-  [WebGL test #14: getError expected: INVALID_VALUE. Was NO_ERROR : uniformMatrix4fv should return INVALID_VALUE with transpose = true]
-    expected: FAIL
-
diff --git a/tests/wpt/mozilla/meta/webgl/conformance-1.0.3/conformance/uniforms/uniform-default-values.html.ini b/tests/wpt/mozilla/meta/webgl/conformance-1.0.3/conformance/uniforms/uniform-default-values.html.ini
index bbd7c84970e..d438933647c 100644
--- a/tests/wpt/mozilla/meta/webgl/conformance-1.0.3/conformance/uniforms/uniform-default-values.html.ini
+++ b/tests/wpt/mozilla/meta/webgl/conformance-1.0.3/conformance/uniforms/uniform-default-values.html.ini
@@ -1,9 +1,5 @@
 [uniform-default-values.html]
-  type: testharness
   expected: ERROR
-  [WebGL uniform default values]
-    expected: FAIL
-
   [Overall test]
     expected: NOTRUN
 
diff --git a/tests/wpt/mozilla/meta/webgl/conformance-1.0.3/conformance/uniforms/uniform-location.html.ini b/tests/wpt/mozilla/meta/webgl/conformance-1.0.3/conformance/uniforms/uniform-location.html.ini
index 21de226cc01..fb6c9c25e94 100644
--- a/tests/wpt/mozilla/meta/webgl/conformance-1.0.3/conformance/uniforms/uniform-location.html.ini
+++ b/tests/wpt/mozilla/meta/webgl/conformance-1.0.3/conformance/uniforms/uniform-location.html.ini
@@ -1,5 +1,4 @@
 [uniform-location.html]
-  type: testharness
   [WebGL test #9: contextA.getUniform(programS, locationSx) should be 333. Threw exception TypeError: contextA.getUniform is not a function]
     expected: FAIL
 
diff --git a/tests/wpt/mozilla/meta/webgl/conformance-1.0.3/conformance/uniforms/uniform-samplers-test.html.ini b/tests/wpt/mozilla/meta/webgl/conformance-1.0.3/conformance/uniforms/uniform-samplers-test.html.ini
deleted file mode 100644
index 77a8b35d2d4..00000000000
--- a/tests/wpt/mozilla/meta/webgl/conformance-1.0.3/conformance/uniforms/uniform-samplers-test.html.ini
+++ /dev/null
@@ -1,3 +0,0 @@
-[uniform-samplers-test.html]
-  type: testharness
-  disabled: flaky