Update from https://crrev.com/315085

ui/gl/gl_context.h

Index: ui/gl/gl_context.h
diff --git a/ui/gl/gl_context.h b/ui/gl/gl_context.h
index 62cabcd138b29c669701aa8010b9d6bb2e0a454f..5eac8383f38d40c5afc67a560ea3566208735327 100644
--- a/ui/gl/gl_context.h
+++ b/ui/gl/gl_context.h
@@ -34,25 +34,6 @@ class GL_EXPORT GLContext : public base::RefCounted<GLContext> {
   virtual bool Initialize(
       GLSurface* compatible_surface, GpuPreference gpu_preference) = 0;
 
-  class FlushEvent : public base::RefCountedThreadSafe<FlushEvent> {
-    public:
-      bool IsSignaled();
-
-    private:
-      friend class base::RefCountedThreadSafe<FlushEvent>;
-      friend class GLContext;
-      FlushEvent();
-      virtual ~FlushEvent();
-      void Signal();
-
-      base::CancellationFlag flag_;
-  };
-
-  // Needs to be called with this context current. It will return a FlushEvent
-  // that is initially unsignaled, but will transition to signaled after the
-  // next glFlush() or glFinish() occurs in this context.
-  scoped_refptr<FlushEvent> SignalFlush();
-
   // Destroys the GL context.
   virtual void Destroy() = 0;
 
@@ -143,9 +124,6 @@ class GL_EXPORT GLContext : public base::RefCounted<GLContext> {
   // Returns the GL renderer string. The context must be current.
   virtual std::string GetGLRenderer();
 
-  // Called when glFlush()/glFinish() is called with this context current.
-  void OnFlush();
-
  protected:
   virtual ~GLContext();
 
@@ -186,8 +164,6 @@ class GL_EXPORT GLContext : public base::RefCounted<GLContext> {
   scoped_ptr<GLStateRestorer> state_restorer_;
   scoped_ptr<GLVersionInfo> version_info_;
 
-  std::vector<scoped_refptr<FlushEvent> > flush_events_;
-
   int swap_interval_;
   bool force_swap_interval_zero_;