diff --git a/components/style/font_face.rs b/components/style/font_face.rs
index 54ffdcc7891..90caaa0b2d8 100644
--- a/components/style/font_face.rs
+++ b/components/style/font_face.rs
@@ -9,20 +9,21 @@ use properties::longhands::font_family::parse_one_family;
 use std::ascii::AsciiExt;
 use string_cache::Atom;
 use url::{Url, UrlParser};
+use util::mem::HeapSizeOf;
 
-#[derive(Clone, Debug, PartialEq, Eq, Deserialize, Serialize)]
+#[derive(Clone, Debug, HeapSizeOf, PartialEq, Eq, Deserialize, Serialize)]
 pub enum Source {
     Url(UrlSource),
     Local(Atom),
 }
 
-#[derive(Clone, Debug, PartialEq, Eq, Deserialize, Serialize)]
+#[derive(Clone, Debug, HeapSizeOf, PartialEq, Eq, Deserialize, Serialize)]
 pub struct UrlSource {
     pub url: Url,
     pub format_hints: Vec<String>,
 }
 
-#[derive(Debug, PartialEq, Eq)]
+#[derive(Debug, HeapSizeOf, PartialEq, Eq)]
 pub struct FontFaceRule {
     pub family: Atom,
     pub sources: Vec<Source>,
diff --git a/components/style/media_queries.rs b/components/style/media_queries.rs
index 76516747bd1..066fc76528d 100644
--- a/components/style/media_queries.rs
+++ b/components/style/media_queries.rs
@@ -8,15 +8,16 @@ use euclid::size::{Size2D, TypedSize2D};
 use properties::longhands;
 use std::ascii::AsciiExt;
 use util::geometry::ViewportPx;
+use util::mem::HeapSizeOf;
 use values::specified;
 
 
-#[derive(Debug, PartialEq)]
+#[derive(Debug, HeapSizeOf, PartialEq)]
 pub struct MediaQueryList {
     pub media_queries: Vec<MediaQuery>
 }
 
-#[derive(PartialEq, Eq, Copy, Clone, Debug)]
+#[derive(PartialEq, Eq, Copy, Clone, Debug, HeapSizeOf)]
 pub enum Range<T> {
     Min(T),
     Max(T),
@@ -59,20 +60,20 @@ impl<T: Ord> Range<T> {
 }
 
 /// http://dev.w3.org/csswg/mediaqueries-3/#media1
-#[derive(PartialEq, Copy, Clone, Debug)]
+#[derive(PartialEq, Copy, Clone, Debug, HeapSizeOf)]
 pub enum Expression {
     /// http://dev.w3.org/csswg/mediaqueries-3/#width
     Width(Range<specified::Length>),
 }
 
 /// http://dev.w3.org/csswg/mediaqueries-3/#media0
-#[derive(PartialEq, Eq, Copy, Clone, Debug)]
+#[derive(PartialEq, Eq, Copy, Clone, Debug, HeapSizeOf)]
 pub enum Qualifier {
     Only,
     Not,
 }
 
-#[derive(Debug, PartialEq)]
+#[derive(Debug, HeapSizeOf, PartialEq)]
 pub struct MediaQuery {
     pub qualifier: Option<Qualifier>,
     pub media_type: MediaQueryType,
@@ -91,20 +92,20 @@ impl MediaQuery {
 }
 
 /// http://dev.w3.org/csswg/mediaqueries-3/#media0
-#[derive(PartialEq, Eq, Copy, Clone, Debug)]
+#[derive(PartialEq, Eq, Copy, Clone, Debug, HeapSizeOf)]
 pub enum MediaQueryType {
     All,  // Always true
     MediaType(MediaType),
 }
 
-#[derive(PartialEq, Eq, Copy, Clone, Debug)]
+#[derive(PartialEq, Eq, Copy, Clone, Debug, HeapSizeOf)]
 pub enum MediaType {
     Screen,
     Print,
     Unknown,
 }
 
-#[derive(Debug)]
+#[derive(Debug, HeapSizeOf)]
 pub struct Device {
     pub media_type: MediaType,
     pub viewport_size: TypedSize2D<ViewportPx, f32>,
diff --git a/components/style/stylesheets.rs b/components/style/stylesheets.rs
index c9d5354238a..0b1decedc31 100644
--- a/components/style/stylesheets.rs
+++ b/components/style/stylesheets.rs
@@ -17,12 +17,13 @@ use std::iter::Iterator;
 use std::slice;
 use string_cache::{Atom, Namespace};
 use url::Url;
+use util::mem::HeapSizeOf;
 use viewport::ViewportRule;
 
 /// Each style rule has an origin, which determines where it enters the cascade.
 ///
 /// http://dev.w3.org/csswg/css-cascade/#cascading-origins
-#[derive(Clone, PartialEq, Eq, Copy, Debug)]
+#[derive(Clone, PartialEq, Eq, Copy, Debug, HeapSizeOf)]
 pub enum Origin {
     /// http://dev.w3.org/csswg/css-cascade/#cascade-origin-ua
     UserAgent,
@@ -35,7 +36,7 @@ pub enum Origin {
 }
 
 
-#[derive(Debug, PartialEq)]
+#[derive(Debug, HeapSizeOf, PartialEq)]
 pub struct Stylesheet {
     /// List of rules in the order they were found (important for
     /// cascading order)
@@ -44,7 +45,7 @@ pub struct Stylesheet {
 }
 
 
-#[derive(Debug, PartialEq)]
+#[derive(Debug, HeapSizeOf, PartialEq)]
 pub enum CSSRule {
     Charset(String),
     Namespace(Option<String>, Namespace),
@@ -54,7 +55,7 @@ pub enum CSSRule {
     Viewport(ViewportRule),
 }
 
-#[derive(Debug, PartialEq)]
+#[derive(Debug, HeapSizeOf, PartialEq)]
 pub struct MediaRule {
     pub media_queries: MediaQueryList,
     pub rules: Vec<CSSRule>,
@@ -67,7 +68,7 @@ impl MediaRule {
     }
 }
 
-#[derive(Debug, PartialEq)]
+#[derive(Debug, HeapSizeOf, PartialEq)]
 pub struct StyleRule {
     pub selectors: Vec<Selector>,
     pub declarations: PropertyDeclarationBlock,
diff --git a/components/style/viewport.rs b/components/style/viewport.rs
index 226edda1fd9..698015686a1 100644
--- a/components/style/viewport.rs
+++ b/components/style/viewport.rs
@@ -18,10 +18,11 @@ use std::str::Chars;
 use style_traits::viewport::{Orientation, UserZoom, ViewportConstraints, Zoom};
 use stylesheets::Origin;
 use util::geometry::ViewportPx;
+use util::mem::HeapSizeOf;
 use values::computed::{Context, ToComputedValue};
 use values::specified::{Length, LengthOrPercentageOrAuto, ViewportPercentageLength};
 
-#[derive(Copy, Clone, Debug, PartialEq)]
+#[derive(Copy, Clone, Debug, HeapSizeOf, PartialEq)]
 pub enum ViewportDescriptor {
     MinWidth(ViewportLength),
     MaxWidth(ViewportLength),
@@ -133,7 +134,7 @@ struct ViewportRuleParser<'a, 'b: 'a> {
     context: &'a ParserContext<'b>
 }
 
-#[derive(Copy, Clone, Debug, PartialEq)]
+#[derive(Copy, Clone, Debug, HeapSizeOf, PartialEq)]
 pub struct ViewportDescriptorDeclaration {
     pub origin: Origin,
     pub descriptor: ViewportDescriptor,
@@ -228,7 +229,7 @@ impl<'a, 'b> DeclarationParser for ViewportRuleParser<'a, 'b> {
     }
 }
 
-#[derive(Debug, PartialEq)]
+#[derive(Debug, HeapSizeOf, PartialEq)]
 pub struct ViewportRule {
     pub declarations: Vec<ViewportDescriptorDeclaration>
 }
diff --git a/components/style_traits/viewport.rs b/components/style_traits/viewport.rs
index 186fc6f2f17..cead903301a 100644
--- a/components/style_traits/viewport.rs
+++ b/components/style_traits/viewport.rs
@@ -20,7 +20,7 @@ define_css_keyword_enum!(Orientation:
                          "landscape" => Landscape);
 
 
-#[derive(Clone, Debug, PartialEq, Deserialize, Serialize)]
+#[derive(Clone, Debug, HeapSizeOf, PartialEq, Deserialize, Serialize)]
 pub struct ViewportConstraints {
     pub size: TypedSize2D<ViewportPx, f32>,
 
@@ -54,7 +54,7 @@ impl ToCss for ViewportConstraints {
 
 /// Zoom is a number | percentage | auto
 /// See http://dev.w3.org/csswg/css-device-adapt/#descdef-viewport-zoom
-#[derive(Copy, Clone, Debug, PartialEq)]
+#[derive(Copy, Clone, Debug, HeapSizeOf, PartialEq)]
 pub enum Zoom {
     Number(f32),
     Percentage(f32),