Refactored GLContext to own GPUTiming which spawn GPUTimingClients.

ui/gl/gl_context.cc

Index: ui/gl/gl_context.cc
diff --git a/ui/gl/gl_context.cc b/ui/gl/gl_context.cc
index 720e8e23513c534efe37bea129a11d5fd4831c52..3feecf54f7b9c6193668197dec6a7cb89cdd94af 100644
--- a/ui/gl/gl_context.cc
+++ b/ui/gl/gl_context.cc
@@ -15,6 +15,7 @@
 #include "ui/gl/gl_surface.h"
 #include "ui/gl/gl_switches.h"
 #include "ui/gl/gl_version_info.h"
+#include "ui/gl/gpu_timing.h"
 
 namespace gfx {
 
@@ -112,6 +113,13 @@ const GLVersionInfo* GLContext::GetVersionInfo() {
   return version_info_.get();
 }
 
+gpu::GPUTiming* GLContext::GetGPUTiming() {
+  if (!gpu_timing_) {
+    gpu_timing_ = make_scoped_ptr(new gpu::GPUTiming(this));
+  }
+  return gpu_timing_.get();
+}
+
 GLShareGroup* GLContext::share_group() {
   return share_group_.get();
 }