Backed out changeset 23c6326dd926 (bug 1382077) on request from xidorn

layout/base/nsPresContext.cpp

@@ -2117,9 +2117,8 @@ nsPresContext::MediaFeatureValuesChanged(nsRestyleHint aRestyleHint,
   mPendingMediaFeatureValuesChanged = false;
 
   // MediumFeaturesChanged updates the applied rules, so it always gets called.
-  if (mShell) {
-    aRestyleHint |= mShell->
-      StyleSet()->MediumFeaturesChanged(mPendingViewportChange);
+  if (mShell && mShell->StyleSet()->MediumFeaturesChanged()) {
+    aRestyleHint |= eRestyle_Subtree;
   }
 
   if (mPendingViewportChange &&

layout/style/ServoStyleSet.cpp

@@ -113,13 +113,10 @@ ServoStyleSet::InvalidateStyleForCSSRuleChanges()
   mPresContext->RestyleManager()->AsServo()->PostRestyleEventForCSSRuleChanges();
 }
 
-nsRestyleHint
-ServoStyleSet::MediumFeaturesChanged(bool aViewportChanged) const
+bool
+ServoStyleSet::MediumFeaturesChanged() const
 {
-  if (Servo_StyleSet_MediumFeaturesChanged(mRawSet.get())) {
-    return eRestyle_Subtree;
-  }
-  return nsRestyleHint(0);
+  return Servo_StyleSet_MediumFeaturesChanged(mRawSet.get());
 }
 
 size_t

layout/style/ServoStyleSet.h

@@ -115,7 +115,7 @@ public:
     return StylistNeedsUpdate();
   }
 
-  nsRestyleHint MediumFeaturesChanged(bool aViewportChanged) const;
+  bool MediumFeaturesChanged() const;
 
   void InvalidateStyleForCSSRuleChanges();
 

layout/style/StyleSetHandle.h

@@ -160,7 +160,7 @@ public:
     inline void RecordShadowStyleChange(mozilla::dom::ShadowRoot* aShadowRoot);
     inline bool StyleSheetsHaveChanged() const;
     inline void InvalidateStyleForCSSRuleChanges();
-    inline nsRestyleHint MediumFeaturesChanged(bool aViewportChanged);
+    inline bool MediumFeaturesChanged();
     inline already_AddRefed<nsStyleContext>
     ProbePseudoElementStyle(dom::Element* aParentElement,
                             mozilla::CSSPseudoElementType aType,

layout/style/StyleSetHandleInlines.h

@@ -256,10 +256,10 @@ StyleSetHandle::Ptr::StyleSheetsHaveChanged() const
 {
   FORWARD(StyleSheetsHaveChanged, ());
 }
-nsRestyleHint
-StyleSetHandle::Ptr::MediumFeaturesChanged(bool aViewportChanged)
+bool
+StyleSetHandle::Ptr::MediumFeaturesChanged()
 {
-  FORWARD(MediumFeaturesChanged, (aViewportChanged));
+  FORWARD(MediumFeaturesChanged, ());
 }
 void
 StyleSetHandle::Ptr::InvalidateStyleForCSSRuleChanges()

layout/style/nsStyleSet.cpp

@@ -2674,8 +2674,8 @@ nsStyleSet::HasAttributeDependentStyle(Element*       aElement,
   return data.mHint;
 }
 
-nsRestyleHint
-nsStyleSet::MediumFeaturesChanged(bool aViewportChanged)
+bool
+nsStyleSet::MediumFeaturesChanged()
 {
   NS_ASSERTION(mBatching == 0, "rule processors out of date");
 
@@ -2700,10 +2700,7 @@ nsStyleSet::MediumFeaturesChanged(bool aViewportChanged)
     stylesChanged = stylesChanged || thisChanged;
   }
 
-  if (stylesChanged) {
-    return eRestyle_Subtree;
-  }
-  return nsRestyleHint(0);
+  return stylesChanged;
 }
 
 bool

layout/style/nsStyleSet.h

@@ -380,10 +380,10 @@ class nsStyleSet final
 
   /*
    * Do any processing that needs to happen as a result of a change in
-   * the characteristics of the medium, and return restyle hint needed
-   * for the change.
+   * the characteristics of the medium, and return whether style rules
+   * may have changed as a result.
    */
-  nsRestyleHint MediumFeaturesChanged(bool aViewportChanged);
+  bool MediumFeaturesChanged();
 
   // APIs to manipulate the style sheet lists.  The sheets in each
   // list are stored with the most significant sheet last.