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..1ba61d0c33a9b2e37f660adfd8e37bd86bd93659 100644
--- a/ui/gl/gl_context.h
+++ b/ui/gl/gl_context.h
@@ -16,6 +16,10 @@
 #include "ui/gl/gl_state_restorer.h"
 #include "ui/gl/gpu_preference.h"
 
+namespace gpu {
+  class GPUTiming;
+}
+
 namespace gfx {
 
 class GLSurface;
@@ -91,6 +95,10 @@ class GL_EXPORT GLContext : public base::RefCounted<GLContext> {
   // current.
   const GLVersionInfo* GetVersionInfo();
 
+  // Returns a GPUTiming object used to create GPUTimingClients. This class
+  // is used to abstract the various GPU Timing extensions.
+  gpu::GPUTiming* GetGPUTiming();

[vmiura, 2015/02/24 23:57:59]

Do we need to return GPUTiming?  Can we have just have direct
CreateGPUTimingClient()?

Also, this should be virtual. GLContextVirtual needs to pass through to the real
underlying shared_context_.

[vmiura, 2015/02/25 00:10:38]

Oh, probably make CreateGPUTimingClient() pure virtual here, and add
implementations to GlContextReal and GlContextVirtual.

[David Yen, 2015/02/25 01:47:35]

Done.

+
   GLShareGroup* share_group();
 
   // Create a GL context that is compatible with the given surface.
@@ -163,6 +171,7 @@ class GL_EXPORT GLContext : public base::RefCounted<GLContext> {
   scoped_ptr<VirtualGLApi> virtual_gl_api_;
   scoped_ptr<GLStateRestorer> state_restorer_;
   scoped_ptr<GLVersionInfo> version_info_;
+  scoped_ptr<gpu::GPUTiming> gpu_timing_;
 
   int swap_interval_;
   bool force_swap_interval_zero_;