--- a/dom/base/ResponsiveImageSelector.cpp
+++ b/dom/base/ResponsiveImageSelector.cpp
@@ -1,16 +1,16 @@
 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include "mozilla/dom/ResponsiveImageSelector.h"
-#include "mozilla/ServoStyleSet.h"
+#include "mozilla/ServoStyleSetInlines.h"
 #include "nsIURI.h"
 #include "nsIDocument.h"
 #include "nsContentUtils.h"
 #include "nsPresContext.h"
 
 #include "nsCSSParser.h"
 #include "nsCSSProps.h"
 

--- a/layout/base/RestyleManager.cpp
+++ b/layout/base/RestyleManager.cpp
@@ -5,16 +5,17 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include "mozilla/RestyleManager.h"
 #include "mozilla/RestyleManagerInlines.h"
 
 #include "Layers.h"
 #include "LayerAnimationInfo.h" // For LayerAnimationInfo::sRecords
 #include "mozilla/StyleSetHandleInlines.h"
+#include "mozilla/ServoStyleSetInlines.h"
 #include "nsAnimationManager.h"
 #include "nsCSSFrameConstructor.h"
 #include "nsCSSRendering.h"
 #include "nsIFrame.h"
 #include "nsIFrameInlines.h"
 #include "nsIPresShellInlines.h"
 #include "nsPlaceholderFrame.h"
 #include "nsStyleChangeList.h"

--- a/layout/base/nsCSSFrameConstructor.cpp
+++ b/layout/base/nsCSSFrameConstructor.cpp
@@ -19,16 +19,17 @@
 #include "mozilla/dom/HTMLSelectElement.h"
 #include "mozilla/dom/HTMLSummaryElement.h"
 #include "mozilla/EventStates.h"
 #include "mozilla/Likely.h"
 #include "mozilla/LinkedList.h"
 #include "mozilla/MemoryReporting.h"
 #include "mozilla/PresShell.h"
 #include "mozilla/ServoBindings.h"
+#include "mozilla/ServoStyleSetInlines.h"
 #include "nsAbsoluteContainingBlock.h"
 #include "nsCSSPseudoElements.h"
 #include "nsAtom.h"
 #include "nsIFrameInlines.h"
 #include "nsGkAtoms.h"
 #include "nsPresContext.h"
 #include "nsIDocument.h"
 #include "nsIDocumentInlines.h"

--- a/layout/style/ServoStyleSet.cpp
+++ b/layout/style/ServoStyleSet.cpp
@@ -1,15 +1,16 @@
 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include "mozilla/ServoStyleSet.h"
+#include "mozilla/ServoStyleSetInlines.h"
 
 #include "gfxPlatformFontList.h"
 #include "mozilla/AutoRestyleTimelineMarker.h"
 #include "mozilla/DocumentStyleRootIterator.h"
 #include "mozilla/IntegerRange.h"
 #include "mozilla/LookAndFeel.h"
 #include "mozilla/RestyleManagerInlines.h"
 #include "mozilla/ServoBindings.h"

--- a/layout/style/ServoStyleSet.h
+++ b/layout/style/ServoStyleSet.h
@@ -8,17 +8,16 @@
 #define mozilla_ServoStyleSet_h
 
 #include "mozilla/AtomArray.h"
 #include "mozilla/EnumeratedArray.h"
 #include "mozilla/EventStates.h"
 #include "mozilla/MediaFeatureChange.h"
 #include "mozilla/PostTraversalTask.h"
 #include "mozilla/ServoBindingTypes.h"
-#include "mozilla/ServoBindings.h"
 #include "mozilla/ServoUtils.h"
 #include "mozilla/SheetType.h"
 #include "mozilla/UniquePtr.h"
 #include "MainThreadUtils.h"
 #include "nsCSSPseudoElements.h"
 #include "nsCSSAnonBoxes.h"
 #include "nsChangeHint.h"
 #include "nsCoord.h"
@@ -128,19 +127,18 @@ public:
 
   nsRestyleHint MediumFeaturesChanged(MediaFeatureChangeReason);
 
   // Evaluates a given SourceSizeList, returning the optimal viewport width in
   // app units.
   //
   // The SourceSizeList parameter can be null, in which case it will return
   // 100vw.
-  nscoord EvaluateSourceSizeList(const RawServoSourceSizeList* aSourceSizeList) const {
-    return Servo_SourceSizeList_Evaluate(mRawSet.get(), aSourceSizeList);
-  }
+  inline nscoord EvaluateSourceSizeList(
+      const RawServoSourceSizeList* aSourceSizeList) const;
 
   void InvalidateStyleForCSSRuleChanges();
 
   void AddSizeOfIncludingThis(nsWindowSizes& aSizes) const;
   const RawServoStyleSet* RawSet() const {
     return mRawSet.get();
   }
 
@@ -337,20 +335,18 @@ public:
   void CompatibilityModeChanged();
 
   /**
    * Resolve style for the given element, and return it as a
    * ComputedStyle.
    *
    * FIXME(emilio): Is there a point in this after bug 1367904?
    */
-  already_AddRefed<ComputedStyle> ResolveServoStyle(dom::Element* aElement)
-  {
-    return Servo_ResolveStyle(aElement, mRawSet.get()).Consume();
-  }
+  inline already_AddRefed<ComputedStyle>
+    ResolveServoStyle(dom::Element* aElement);
 
   bool GetKeyframesForName(nsAtom* aName,
                            const nsTimingFunction& aTimingFunction,
                            nsTArray<Keyframe>& aKeyframes);
 
   nsTArray<ComputedKeyframeValues>
   GetComputedKeyframeValuesFor(const nsTArray<Keyframe>& aKeyframes,
                                dom::Element* aElement,

new file mode 100644
--- /dev/null
+++ b/layout/style/ServoStyleSetInlines.h
@@ -0,0 +1,26 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_ServoStyleSetInlines_h
+#define mozilla_ServoStyleSetInlines_h
+
+#include "mozilla/ServoStyleSet.h"
+#include "mozilla/ServoBindings.h"
+
+nscoord
+ServoStyleSet::EvaluateSourceSizeList(
+  const RawServoSourceSizeList* aSourceSizeList) const
+{
+  return Servo_SourceSizeList_Evaluate(mRawSet.get(), aSourceSizeList);
+}
+
+already_AddRefed<ComputedStyle>
+ServoStyleSet::ResolveServoStyle(dom::Element* aElement)
+{
+  return Servo_ResolveStyle(aElement, mRawSet.get()).Consume();
+}
+
+#endif // mozilla_ServoStyleSetInlines_h

--- a/layout/style/moz.build
+++ b/layout/style/moz.build
@@ -97,16 +97,17 @@ EXPORTS.mozilla += [
     'ServoMediaList.h',
     'ServoMediaRule.h',
     'ServoNamespaceRule.h',
     'ServoPageRule.h',
     'ServoPropPrefList.h',
     'ServoSpecifiedValues.h',
     'ServoStyleRule.h',
     'ServoStyleSet.h',
+    'ServoStyleSetInlines.h',
     'ServoStyleSheet.h',
     'ServoSupportsRule.h',
     'ServoTraversalStatistics.h',
     'ServoTypes.h',
     'ServoUtils.h',
     'SheetType.h',
     'StyleAnimationValue.h',
     'StyleComplexColor.h',