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

content/common/gpu/gpu_channel.cc

Index: content/common/gpu/gpu_channel.cc
===================================================================
--- content/common/gpu/gpu_channel.cc	(revision 137679)
+++ content/common/gpu/gpu_channel.cc	(working copy)
@@ -179,6 +179,11 @@
     int32 surface_id,
     const GPUCreateCommandBufferConfig& init_params,
     int32* route_id) {
+  TRACE_EVENT1("gpu",
+               "GpuChannel::CreateViewCommandBuffer",
+               "surface_id",
+               surface_id);
+
   *route_id = MSG_ROUTING_NONE;
   content::GetContentClient()->SetActiveURL(init_params.active_url);
 
@@ -336,6 +341,8 @@
     const gfx::Size& size,
     const GPUCreateCommandBufferConfig& init_params,
     IPC::Message* reply_message) {
+  TRACE_EVENT0("gpu", "GpuChannel::OnCreateOffscreenCommandBuffer");
+
   int32 route_id = MSG_ROUTING_NONE;
 
   content::GetContentClient()->SetActiveURL(init_params.active_url);
@@ -373,9 +380,10 @@
 
 void GpuChannel::OnDestroyCommandBuffer(int32 route_id,
                                         IPC::Message* reply_message) {
-#if defined(ENABLE_GPU)
   TRACE_EVENT1("gpu", "GpuChannel::OnDestroyCommandBuffer",
                "route_id", route_id);
+
+#if defined(ENABLE_GPU)

[piman, 2012/05/17 22:30:03]

nit: Just remove #ifdef altogether, since we don't support enable_gpu=0 any
more?

   if (router_.ResolveRoute(route_id)) {
     GpuCommandBufferStub* stub = stubs_.Lookup(route_id);
     bool need_reschedule = (stub && !stub->IsScheduled());