Rework dispatchEvent so it is consistent for isTrusted support.

Source/core/html/track/TextTrackCue.h

Index: Source/core/html/track/TextTrackCue.h
diff --git a/Source/core/html/track/TextTrackCue.h b/Source/core/html/track/TextTrackCue.h
index 4402104f5f10314e8aace06a582e2b717346ddb6..34cbc0a1e508b4ee52c91f4ff26439542dd01f80 100644
--- a/Source/core/html/track/TextTrackCue.h
+++ b/Source/core/html/track/TextTrackCue.h
@@ -74,9 +74,6 @@ public:
     void updateCueIndex(unsigned cueIndex) { m_cueIndex = cueIndex; }
     void invalidateCueIndex();
 
-    using EventTarget::dispatchEvent;
-    bool dispatchEvent(PassRefPtrWillBeRawPtr<Event>) override;
-
     bool isActive() const { return m_isActive; }
     void setIsActive(bool active) { m_isActive = active; }
 
@@ -112,6 +109,7 @@ protected:
 
     void cueWillChange();
     virtual void cueDidChange();
+    bool dispatchEventInternal(PassRefPtrWillBeRawPtr<Event>) override;
 
 private:
     AtomicString m_id;