Improve detection of touch events when hiding media controls.

Source/core/events/MouseRelatedEvent.h

Index: Source/core/events/MouseRelatedEvent.h
diff --git a/Source/core/events/MouseRelatedEvent.h b/Source/core/events/MouseRelatedEvent.h
index 21dc6a54cc78b941ae8cf5720f8c399da3a3cab4..75659c38f1b0185b448ffea5243e5904a17f3141 100644
--- a/Source/core/events/MouseRelatedEvent.h
+++ b/Source/core/events/MouseRelatedEvent.h
@@ -47,6 +47,7 @@ namespace blink {
         int offsetX();
         int offsetY();
         bool isSimulated() const { return m_isSimulated; }
+        bool derivesFromTouch() const { return m_derivesFromTouch; }
         virtual int pageX() const OVERRIDE FINAL;
         virtual int pageY() const OVERRIDE FINAL;
         int x() const;
@@ -61,10 +62,10 @@ namespace blink {
 
     protected:
         MouseRelatedEvent();
-        MouseRelatedEvent(const AtomicString& type, bool canBubble, bool cancelable, PassRefPtrWillBeRawPtr<AbstractView>,
-                          int detail, const IntPoint& screenLocation, const IntPoint& windowLocation,
-                          const IntPoint& movementDelta,
-                          bool ctrlKey, bool altKey, bool shiftKey, bool metaKey, bool isSimulated = false);
+        MouseRelatedEvent(const AtomicString& type, bool canBubble, bool cancelable,
+            PassRefPtrWillBeRawPtr<AbstractView>, int detail, const IntPoint& screenLocation,
+            const IntPoint& windowLocation, const IntPoint& movementDelta, bool ctrlKey, bool altKey,
+            bool shiftKey, bool metaKey, bool isSimulated = false, bool derivesFromTouch = false);
 
         void initCoordinates();
         void initCoordinates(const LayoutPoint& clientLocation);
@@ -85,6 +86,7 @@ namespace blink {
         LayoutPoint m_absoluteLocation;
         bool m_isSimulated;
         bool m_hasCachedRelativePosition;
+        bool m_derivesFromTouch;
     };
 
 } // namespace blink