Add trace events to measure GPU process startup timing and time to first present.

content/renderer/render_thread_impl.cc

Index: content/renderer/render_thread_impl.cc
===================================================================
--- content/renderer/render_thread_impl.cc	(revision 137679)
+++ content/renderer/render_thread_impl.cc	(working copy)
@@ -766,6 +766,11 @@
 
 int32 RenderThreadImpl::CreateViewCommandBuffer(
       int32 surface_id, const GPUCreateCommandBufferConfig& init_params) {
+  TRACE_EVENT1("gpu",
+               "RenderThreadImpl::CreateViewCommandBuffer",
+               "surface_id",
+               surface_id);
+
   int32 route_id = MSG_ROUTING_NONE;
   IPC::Message* message = new GpuHostMsg_CreateViewCommandBuffer(
       surface_id,
@@ -884,6 +889,8 @@
 
 GpuChannelHost* RenderThreadImpl::EstablishGpuChannelSync(
     content::CauseForGpuLaunch cause_for_gpu_launch) {
+  TRACE_EVENT0("gpu", "RenderThreadImpl::EstablishGpuChannelSync");
+
   if (gpu_channel_.get()) {
     // Do nothing if we already have a GPU channel or are already
     // establishing one.