diff --git a/components/selectors/parser.rs b/components/selectors/parser.rs
index 45ff70df416..c17e8af1a71 100644
--- a/components/selectors/parser.rs
+++ b/components/selectors/parser.rs
@@ -423,7 +423,6 @@ impl<Impl: SelectorImpl> Selector<Impl> {
         ))
     }
 
-
     /// Returns an iterator over this selector in matching order (right-to-left).
     /// When a combinator is reached, the iterator will return None, and
     /// next_sequence() may be called to continue to the next sequence.
@@ -494,6 +493,11 @@ impl<Impl: SelectorImpl> Selector<Impl> {
     pub fn len(&self) -> usize {
         self.0.slice.len()
     }
+
+    /// Returns the address on the heap of the ThinArc for memory reporting.
+    pub fn thin_arc_heap_ptr(&self) -> *const ::std::os::raw::c_void {
+        self.0.heap_ptr()
+    }
 }
 
 #[derive(Clone)]
diff --git a/components/servo_arc/lib.rs b/components/servo_arc/lib.rs
index 2d0dbd8236c..5cac8c9b9bb 100644
--- a/components/servo_arc/lib.rs
+++ b/components/servo_arc/lib.rs
@@ -676,6 +676,12 @@ impl<H: 'static, T: 'static> ThinArc<H, T> {
         // Forward the result.
         result
     }
+
+    /// Returns the address on the heap of the ThinArc itself -- not the T
+    /// within it -- for memory reporting.
+    pub fn heap_ptr(&self) -> *const c_void {
+        self.ptr as *const ArcInner<T> as *const c_void
+    }
 }
 
 impl<H, T> Deref for ThinArc<H, T> {
diff --git a/components/style/stylesheets/document_rule.rs b/components/style/stylesheets/document_rule.rs
index 5465a4b9759..327994ad3ae 100644
--- a/components/style/stylesheets/document_rule.rs
+++ b/components/style/stylesheets/document_rule.rs
@@ -13,7 +13,7 @@ use servo_arc::Arc;
 use shared_lock::{DeepCloneParams, DeepCloneWithLock, Locked, SharedRwLock, SharedRwLockReadGuard, ToCssWithGuard};
 use std::fmt;
 use style_traits::{ToCss, ParseError, StyleParseError};
-use stylesheets::CssRules;
+use stylesheets::{CssRules, MallocSizeOfFn, MallocSizeOfWithGuard};
 use values::specified::url::SpecifiedUrl;
 
 #[derive(Debug)]
@@ -27,6 +27,15 @@ pub struct DocumentRule {
     pub source_location: SourceLocation,
 }
 
+impl DocumentRule {
+    /// Measure heap usage.
+    pub fn malloc_size_of_children(&self, guard: &SharedRwLockReadGuard,
+                                   malloc_size_of: MallocSizeOfFn) -> usize {
+        // Measurement of other fields may be added later.
+        self.rules.read_with(guard).malloc_size_of_children(guard, malloc_size_of)
+    }
+}
+
 impl ToCssWithGuard for DocumentRule {
     fn to_css<W>(&self, guard: &SharedRwLockReadGuard, dest: &mut W) -> fmt::Result
     where W: fmt::Write {
diff --git a/components/style/stylesheets/media_rule.rs b/components/style/stylesheets/media_rule.rs
index 4eb68999113..f336dc12d89 100644
--- a/components/style/stylesheets/media_rule.rs
+++ b/components/style/stylesheets/media_rule.rs
@@ -12,7 +12,7 @@ use servo_arc::Arc;
 use shared_lock::{DeepCloneParams, DeepCloneWithLock, Locked, SharedRwLock, SharedRwLockReadGuard, ToCssWithGuard};
 use std::fmt;
 use style_traits::ToCss;
-use stylesheets::CssRules;
+use stylesheets::{CssRules, MallocSizeOfFn, MallocSizeOfWithGuard};
 
 /// An [`@media`][media] urle.
 ///
@@ -27,6 +27,15 @@ pub struct MediaRule {
     pub source_location: SourceLocation,
 }
 
+impl MediaRule {
+    /// Measure heap usage.
+    pub fn malloc_size_of_children(&self, guard: &SharedRwLockReadGuard,
+                                   malloc_size_of: MallocSizeOfFn) -> usize {
+        // Measurement of other fields may be added later.
+        self.rules.read_with(guard).malloc_size_of_children(guard, malloc_size_of)
+    }
+}
+
 impl ToCssWithGuard for MediaRule {
     // Serialization of MediaRule is not specced.
     // https://drafts.csswg.org/cssom/#serialize-a-css-rule CSSMediaRule
diff --git a/components/style/stylesheets/mod.rs b/components/style/stylesheets/mod.rs
index 78c4e6d2dfb..87ee2b413c0 100644
--- a/components/style/stylesheets/mod.rs
+++ b/components/style/stylesheets/mod.rs
@@ -116,21 +116,40 @@ impl MallocSizeOfWithGuard for CssRule {
         malloc_size_of: MallocSizeOfFn
     ) -> usize {
         match *self {
+            // Not all fields are currently fully measured. Extra measurement
+            // may be added later.
+
+            CssRule::Namespace(_) => 0,
+
+            // We don't need to measure ImportRule::stylesheet because we measure
+            // it on the C++ side in the child list of the ServoStyleSheet.
+            CssRule::Import(_) => 0,
+
             CssRule::Style(ref lock) => {
                 lock.read_with(guard).malloc_size_of_children(guard, malloc_size_of)
             },
-            // Measurement of these fields may be added later.
-            CssRule::Import(_) => 0,
-            CssRule::Media(_) => 0,
+
+            CssRule::Media(ref lock) => {
+                lock.read_with(guard).malloc_size_of_children(guard, malloc_size_of)
+            },
+
             CssRule::FontFace(_) => 0,
             CssRule::FontFeatureValues(_) => 0,
             CssRule::CounterStyle(_) => 0,
-            CssRule::Keyframes(_) => 0,
-            CssRule::Namespace(_) => 0,
             CssRule::Viewport(_) => 0,
-            CssRule::Supports(_) => 0,
-            CssRule::Page(_) => 0,
-            CssRule::Document(_)  => 0,
+            CssRule::Keyframes(_) => 0,
+
+            CssRule::Supports(ref lock) => {
+                lock.read_with(guard).malloc_size_of_children(guard, malloc_size_of)
+            },
+
+            CssRule::Page(ref lock) => {
+                lock.read_with(guard).malloc_size_of_children(guard, malloc_size_of)
+            },
+
+            CssRule::Document(ref lock) => {
+                lock.read_with(guard).malloc_size_of_children(guard, malloc_size_of)
+            },
         }
     }
 }
diff --git a/components/style/stylesheets/page_rule.rs b/components/style/stylesheets/page_rule.rs
index f47c1316a50..c334df44042 100644
--- a/components/style/stylesheets/page_rule.rs
+++ b/components/style/stylesheets/page_rule.rs
@@ -12,6 +12,7 @@ use servo_arc::Arc;
 use shared_lock::{DeepCloneParams, DeepCloneWithLock, Locked, SharedRwLock, SharedRwLockReadGuard, ToCssWithGuard};
 use std::fmt;
 use style_traits::ToCss;
+use stylesheets::{MallocSizeOf, MallocSizeOfFn};
 
 /// A [`@page`][page] rule.
 ///
@@ -30,6 +31,15 @@ pub struct PageRule {
     pub source_location: SourceLocation,
 }
 
+impl PageRule {
+    /// Measure heap usage.
+    pub fn malloc_size_of_children(&self, guard: &SharedRwLockReadGuard,
+                                   malloc_size_of: MallocSizeOfFn) -> usize {
+        // Measurement of other fields may be added later.
+        self.block.read_with(guard).malloc_size_of_children(malloc_size_of)
+    }
+}
+
 impl ToCssWithGuard for PageRule {
     /// Serialization of PageRule is not specced, adapted from steps for
     /// StyleRule.
diff --git a/components/style/stylesheets/style_rule.rs b/components/style/stylesheets/style_rule.rs
index a66ad7eb5e8..72dbbed0548 100644
--- a/components/style/stylesheets/style_rule.rs
+++ b/components/style/stylesheets/style_rule.rs
@@ -12,7 +12,7 @@ use servo_arc::Arc;
 use shared_lock::{DeepCloneParams, DeepCloneWithLock, Locked, SharedRwLock, SharedRwLockReadGuard, ToCssWithGuard};
 use std::fmt;
 use style_traits::ToCss;
-use stylesheets::{MallocSizeOf, MallocSizeOfFn, MallocSizeOfWithGuard};
+use stylesheets::{MallocSizeOf, MallocSizeOfFn, MallocSizeOfVec, MallocSizeOfWithGuard};
 
 /// A style rule, with selectors and declarations.
 #[derive(Debug)]
@@ -47,8 +47,22 @@ impl MallocSizeOfWithGuard for StyleRule {
         guard: &SharedRwLockReadGuard,
         malloc_size_of: MallocSizeOfFn
     ) -> usize {
-        // Measurement of other fields may be added later.
-        self.block.read_with(guard).malloc_size_of_children(malloc_size_of)
+        let mut n = 0;
+
+        // We may add measurement of things hanging off the embedded Components
+        // later.
+        n += self.selectors.0.malloc_shallow_size_of_vec(malloc_size_of);
+        for selector in self.selectors.0.iter() {
+            // It's safe to measure this ThinArc directly because it's the
+            // "primary" reference. (The secondary references are on the
+            // Stylist.)
+            let ptr = selector.thin_arc_heap_ptr();
+            n += unsafe { (malloc_size_of.0)(ptr) };
+        }
+
+        n += self.block.read_with(guard).malloc_size_of_children(malloc_size_of);
+
+        n
     }
 }
 
diff --git a/components/style/stylesheets/supports_rule.rs b/components/style/stylesheets/supports_rule.rs
index 96c7e7b6cc3..ee5e7516642 100644
--- a/components/style/stylesheets/supports_rule.rs
+++ b/components/style/stylesheets/supports_rule.rs
@@ -13,7 +13,7 @@ use servo_arc::Arc;
 use shared_lock::{DeepCloneParams, DeepCloneWithLock, Locked, SharedRwLock, SharedRwLockReadGuard, ToCssWithGuard};
 use std::fmt;
 use style_traits::{ToCss, ParseError, StyleParseError};
-use stylesheets::{CssRuleType, CssRules};
+use stylesheets::{CssRuleType, CssRules, MallocSizeOfFn, MallocSizeOfWithGuard};
 
 /// An [`@supports`][supports] rule.
 ///
@@ -30,6 +30,15 @@ pub struct SupportsRule {
     pub source_location: SourceLocation,
 }
 
+impl SupportsRule {
+    /// Measure heap usage.
+    pub fn malloc_size_of_children(&self, guard: &SharedRwLockReadGuard,
+                                   malloc_size_of: MallocSizeOfFn) -> usize {
+        // Measurement of other fields may be added later.
+        self.rules.read_with(guard).malloc_size_of_children(guard, malloc_size_of)
+    }
+}
+
 impl ToCssWithGuard for SupportsRule {
     fn to_css<W>(&self, guard: &SharedRwLockReadGuard, dest: &mut W) -> fmt::Result
     where W: fmt::Write {