Add a gpu.SwapBuffers synthetic delay to PostSubBuffer.

gpu/command_buffer/service/gles2_cmd_decoder.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 "gpu/command_buffer/service/gles2_cmd_decoder.h"
 
 #include <stdio.h>
 
 #include <algorithm>
 #include <list>
@@ skipping 7529 matching lines @@
         // Validation should have prevented us from getting here.
         NOTREACHED();
         break;
   }
   return error::kNoError;
 }
 
 error::Error GLES2DecoderImpl::HandlePostSubBufferCHROMIUM(
     uint32 immediate_data_size, const cmds::PostSubBufferCHROMIUM& c) {
   TRACE_EVENT0("gpu", "GLES2DecoderImpl::HandlePostSubBufferCHROMIUM");
+  {
+    TRACE_EVENT_SYNTHETIC_DELAY("gpu.SwapBuffers");

[Zhenyao Mo, 2014/04/17 20:45:48]

I feel you should use a different name from "gpu.SwapBuffers", like
"gpu.PostSubBuffer".  You may have to set the time for the new name in several
places, but in the long run, this avoids any unexpected side-effects /confusion
in the future.

+  }
   if (!supports_post_sub_buffer_) {
     LOCAL_SET_GL_ERROR(
         GL_INVALID_OPERATION,
         "glPostSubBufferCHROMIUM", "command not supported by surface");
     return error::kNoError;
   }
   bool is_tracing;
   TRACE_EVENT_CATEGORY_GROUP_ENABLED(TRACE_DISABLED_BY_DEFAULT("gpu.debug"),
                                      &is_tracing);
   if (is_tracing) {
@@ skipping 3174 matching lines @@
   }
 }
 
 // Include the auto-generated part of this file. We split this because it means
 // we can easily edit the non-auto generated parts right here in this file
 // instead of having to edit some template or the code generator.
 #include "gpu/command_buffer/service/gles2_cmd_decoder_autogen.h"
 
 }  // namespace gles2
 }  // namespace gpu