GPU: Add trace for real SwapBuffers.

ui/gl/gl_surface_x11.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/gl/gl_surface.h"
 
 #include "base/debug/trace_event.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop/message_loop.h"
@@ skipping 167 matching lines @@
   }
 
   return true;
 }
 
 bool NativeViewGLSurfaceOSMesa::IsOffscreen() {
   return false;
 }
 
 bool NativeViewGLSurfaceOSMesa::SwapBuffers() {
+  TRACE_EVENT2("gpu", "NativeViewGLSurfaceOSMesa:RealSwapBuffers",
+      "width", GetSize().width(),
+      "height", GetSize().height());
+
   gfx::Size size = GetSize();
 
   XWindowAttributes attributes;
   if (!XGetWindowAttributes(g_osmesa_display, window_, &attributes)) {
     LOG(ERROR) << "XGetWindowAttributes failed for window " << window_ << ".";
     return false;
   }
 
   // Copy the frame into the pixmap.
   gfx::PutARGBImage(g_osmesa_display,
@@ skipping 129 matching lines @@
     }
     case kGLImplementationMockGL:
       return new GLSurfaceStub;
     default:
       NOTREACHED();
       return NULL;
   }
 }
 
 }  // namespace gfx