Bug 1390694 - Part 1: Add ServoStyleSet function for checking document state dependencies. r=emilio

MozReview-Commit-ID: G8Ju8yHtYx6

--HG--
extra : rebase_source : fc55dfaa52acf490b65650a7101188115a6e4f18

layout/style/ServoBindingList.h

@@ -158,6 +158,9 @@ SERVO_BINDING_FUNC(Servo_StyleSet_HasStateDependency, bool,
                    RawServoStyleSetBorrowed set,
                    RawGeckoElementBorrowed element,
                    uint64_t state)
+SERVO_BINDING_FUNC(Servo_StyleSet_HasDocumentStateDependency, bool,
+                   RawServoStyleSetBorrowed set,
+                   uint64_t state)
 
 // CSSRuleList
 SERVO_BINDING_FUNC(Servo_CssRules_ListTypes, void,

layout/style/ServoStyleSet.cpp

@@ -1582,6 +1582,13 @@ ServoStyleSet::HasStateDependency(const Element& aElement,
       mRawSet.get(), &aElement, aState.ServoValue());
 }
 
+bool
+ServoStyleSet::HasDocumentStateDependency(EventStates aState) const
+{
+  return Servo_StyleSet_HasDocumentStateDependency(
+      mRawSet.get(), aState.ServoValue());
+}
+
 already_AddRefed<ServoStyleContext>
 ServoStyleSet::ReparentStyleContext(ServoStyleContext* aStyleContext,
                                     ServoStyleContext* aNewParent,

layout/style/ServoStyleSet.h

@@ -477,6 +477,12 @@ public:
   bool HasStateDependency(const dom::Element& aElement,
                           EventStates aState) const;
 
+  /**
+   * Returns true if a change in document state might require us to restyle the
+   * document.
+   */
+  bool HasDocumentStateDependency(EventStates aState) const;
+
   /**
    * Get a new style context that uses the same rules as the given style context
    * but has a different parent.