Add a |scope| argument to TRACE_EVENT_INSTANT* and require its presence.

content/browser/gpu/gpu_process_host.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 "content/browser/gpu/gpu_process_host.h"
 
 #include "base/base64.h"
 #include "base/base_switches.h"
 #include "base/bind.h"
 #include "base/bind_helpers.h"
@@ skipping 614 matching lines @@
   BrowserThread::PostTask(BrowserThread::UI,
                           FROM_HERE,
                           base::Bind(&GpuProcessHostUIShim::Destroy,
                                      host_id_,
                                      message));
 }
 
 bool GpuProcessHost::Init() {
   init_start_time_ = base::TimeTicks::Now();
 
-  TRACE_EVENT_INSTANT0("gpu", "LaunchGpuProcess");
+  TRACE_EVENT_INSTANT0("gpu", "LaunchGpuProcess", TRACE_EVENT_SCOPE_THREAD);
 
   std::string channel_id = process_->GetHost()->CreateChannel();
   if (channel_id.empty())
     return false;
 
   if (in_process_) {
     CommandLine::ForCurrentProcess()->AppendSwitch(
         switches::kDisableGpuWatchdog);
 
     in_process_gpu_thread_.reset(new GpuMainThread(channel_id));
@@ skipping 652 matching lines @@
   TRACE_EVENT0("gpu", "GpuProcessHost::OnCacheShader");
   ClientIdToShaderCacheMap::iterator iter =
       client_id_to_shader_cache_.find(client_id);
   // If the cache doesn't exist then this is an off the record profile.
   if (iter == client_id_to_shader_cache_.end())
     return;
   iter->second->Cache(GetShaderPrefixKey() + ":" + key, shader);
 }
 
 }  // namespace content