Addresses Issue: Support OffscreenCanvas as CanvasImageSource #24269

Added methods to canvas_data to support drawing an offscreen canvas onto another canvas
Bug fix: Swapped OffscreenCanvas width and height parameters to match Mozilla spec
Tests: Updated metadata for 866 tests

components/script/dom/offscreencanvas.rs

@@ -16,9 +16,12 @@ use crate::dom::globalscope::GlobalScope;
 use crate::dom::htmlcanvaselement::HTMLCanvasElement;
 use crate::dom::offscreencanvasrenderingcontext2d::OffscreenCanvasRenderingContext2D;
 use crate::script_runtime::JSContext;
+use canvas_traits::canvas::{CanvasMsg, FromScriptMsg};
 use dom_struct::dom_struct;
 use euclid::default::Size2D;
+use ipc_channel::ipc::IpcSharedMemory;
 use js::rust::HandleValue;
+use profile_traits::ipc;
 use ref_filter_map;
 use std::cell::Cell;
 use std::cell::Ref;
@@ -34,22 +37,22 @@ pub enum OffscreenCanvasContext {
 #[dom_struct]
 pub struct OffscreenCanvas {
     eventtarget: EventTarget,
-    height: Cell<u64>,
     width: Cell<u64>,
+    height: Cell<u64>,
     context: DomRefCell<Option<OffscreenCanvasContext>>,
     placeholder: Option<Dom<HTMLCanvasElement>>,
 }
 
 impl OffscreenCanvas {
     pub fn new_inherited(
-        height: u64,
         width: u64,
+        height: u64,
         placeholder: Option<&HTMLCanvasElement>,
     ) -> OffscreenCanvas {
         OffscreenCanvas {
             eventtarget: EventTarget::new_inherited(),
-            height: Cell::new(height),
             width: Cell::new(width),
+            height: Cell::new(height),
             context: DomRefCell::new(None),
             placeholder: placeholder.map(Dom::from_ref),
         }
@@ -57,12 +60,12 @@ impl OffscreenCanvas {
 
     pub fn new(
         global: &GlobalScope,
-        height: u64,
         width: u64,
+        height: u64,
         placeholder: Option<&HTMLCanvasElement>,
     ) -> DomRoot<OffscreenCanvas> {
         reflect_dom_object(
-            Box::new(OffscreenCanvas::new_inherited(height, width, placeholder)),
+            Box::new(OffscreenCanvas::new_inherited(width, height, placeholder)),
             global,
             OffscreenCanvasWrap,
         )
@@ -70,10 +73,10 @@ impl OffscreenCanvas {
 
     pub fn Constructor(
         global: &GlobalScope,
-        height: u64,
         width: u64,
+        height: u64,
     ) -> Fallible<DomRoot<OffscreenCanvas>> {
-        let offscreencanvas = OffscreenCanvas::new(global, height, width, None);
+        let offscreencanvas = OffscreenCanvas::new(global, width, height, None);
         Ok(offscreencanvas)
     }
 
@@ -81,10 +84,44 @@ impl OffscreenCanvas {
         Size2D::new(self.Width(), self.Height())
     }
 
+    pub fn origin_is_clean(&self) -> bool {
+        match *self.context.borrow() {
+            Some(OffscreenCanvasContext::OffscreenContext2d(ref context)) => {
+                context.origin_is_clean()
+            },
+            _ => true,
+        }
+    }
+
     pub fn context(&self) -> Option<Ref<OffscreenCanvasContext>> {
         ref_filter_map::ref_filter_map(self.context.borrow(), |ctx| ctx.as_ref())
     }
 
+    pub fn fetch_all_data(&self) -> Option<(Option<IpcSharedMemory>, Size2D<u32>)> {
+        let size = self.get_size();
+
+        if size.width == 0 || size.height == 0 {
+            return None;
+        }
+
+        let data = match self.context.borrow().as_ref() {
+            Some(&OffscreenCanvasContext::OffscreenContext2d(ref context)) => {
+                let (sender, receiver) =
+                    ipc::channel(self.global().time_profiler_chan().clone()).unwrap();
+                let msg = CanvasMsg::FromScript(
+                    FromScriptMsg::SendPixels(sender),
+                    context.get_canvas_id(),
+                );
+                context.get_ipc_renderer().send(msg).unwrap();
+
+                Some(receiver.recv().unwrap())
+            },
+            None => None,
+        };
+
+        Some((data, size.to_u32()))
+    }
+
     #[allow(unsafe_code)]
     fn get_or_init_2d_context(&self) -> Option<DomRoot<OffscreenCanvasRenderingContext2D>> {
         if let Some(ctx) = self.context() {