Refactored GLContext to own GPUTiming which spawn GPUTimingClients.

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 5eac8383f38d40c5afc67a560ea3566208735327..4577be31cc370673742358c8b76fe465bb15c702 100644
--- a/ui/gl/gl_context.h
+++ b/ui/gl/gl_context.h
@@ -19,9 +19,12 @@
 namespace gfx {
 
 class GLSurface;
+class GPUTiming;
+class GPUTimingClient;
 class VirtualGLApi;
 struct GLVersionInfo;
 
+
 // Encapsulates an OpenGL context, hiding platform specific management.
 class GL_EXPORT GLContext : public base::RefCounted<GLContext> {
  public:
@@ -50,6 +53,9 @@ class GL_EXPORT GLContext : public base::RefCounted<GLContext> {
   // Get the underlying platform specific GL context "handle".
   virtual void* GetHandle() = 0;
 
+  // Creates a GPUTimingClient class which abstracts various GPU Timing exts.
+  virtual scoped_refptr<gfx::GPUTimingClient> CreateGPUTimingClient() = 0;
+
   // Gets the GLStateRestorer for the context.
   GLStateRestorer* GetGLStateRestorer();
 
@@ -173,6 +179,7 @@ class GL_EXPORT GLContext : public base::RefCounted<GLContext> {
 class GL_EXPORT GLContextReal : public GLContext {
  public:
   explicit GLContextReal(GLShareGroup* share_group);
+  scoped_refptr<gfx::GPUTimingClient> CreateGPUTimingClient() override;
 
  protected:
   ~GLContextReal() override;
@@ -180,6 +187,7 @@ class GL_EXPORT GLContextReal : public GLContext {
   void SetCurrent(GLSurface* surface) override;
 
  private:
+  scoped_ptr<gfx::GPUTiming> gpu_timing_;
   DISALLOW_COPY_AND_ASSIGN(GLContextReal);
 };