Send vsync timebase updates to the browser compositor

ui/gl/gl_surface_glx.h

Index: ui/gl/gl_surface_glx.h
diff --git a/ui/gl/gl_surface_glx.h b/ui/gl/gl_surface_glx.h
index 644b51ba2b0323a073d91cca3fb1e21a587d8848..995f3ea389b24c78030389aec773dd62edba41a5 100644
--- a/ui/gl/gl_surface_glx.h
+++ b/ui/gl/gl_surface_glx.h
@@ -27,6 +27,7 @@ class GL_EXPORT GLSurfaceGLX : public GLSurface {
   static const char* GetGLXExtensions();
   static bool HasGLXExtension(const char* name);
   static bool IsCreateContextRobustnessSupported();
+  static bool IsOMLSyncControlSupported();
 
   virtual void* GetDisplay() OVERRIDE;
 
@@ -57,6 +58,9 @@ class GL_EXPORT NativeViewGLSurfaceGLX : public GLSurfaceGLX {
   virtual std::string GetExtensions() OVERRIDE;
   virtual void* GetConfig() OVERRIDE;
   virtual bool PostSubBuffer(int x, int y, int width, int height) OVERRIDE;
+  virtual bool GetSyncValues(int64_t* systemTime,
+                             int64_t* mediaStreamCounter,
+                             int64_t* swapBufferCounter) OVERRIDE;
 
  protected:
   NativeViewGLSurfaceGLX();