Trace the lifetime of CopyOutputRequest

cc/output/copy_output_request.cc

 // Copyright 2013 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 "cc/output/copy_output_request.h"
 
 #include "base/bind.h"
 #include "base/callback_helpers.h"
+#include "base/debug/trace_event.h"
 #include "base/logging.h"
 #include "cc/output/copy_output_result.h"
 #include "cc/resources/single_release_callback.h"
 #include "cc/resources/texture_mailbox.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 
 namespace cc {
 
 // static
 scoped_ptr<CopyOutputRequest> CopyOutputRequest::CreateRelayRequest(
     const CopyOutputRequest& original_request,
     const CopyOutputRequestCallback& result_callback) {
   scoped_ptr<CopyOutputRequest> relay = CreateRequest(result_callback);
   relay->force_bitmap_result_ = original_request.force_bitmap_result_;
   relay->has_area_ = original_request.has_area_;
   relay->area_ = original_request.area_;
   relay->has_texture_mailbox_ = original_request.has_texture_mailbox_;
   relay->texture_mailbox_ = original_request.texture_mailbox_;
   return relay.Pass();
 }
 
 CopyOutputRequest::CopyOutputRequest() {}
 
 CopyOutputRequest::CopyOutputRequest(
     bool force_bitmap_result,
     const CopyOutputRequestCallback& result_callback)
     : force_bitmap_result_(force_bitmap_result),
       has_area_(false),
       has_texture_mailbox_(false),
-      result_callback_(result_callback) {}
+      result_callback_(result_callback) {
+  DCHECK(!result_callback_.is_null());
+  TRACE_EVENT_ASYNC_BEGIN0("cc", "CopyOutputRequest", this);
+}
 
 CopyOutputRequest::~CopyOutputRequest() {
   if (!result_callback_.is_null())
     SendResult(CopyOutputResult::CreateEmptyResult().Pass());
 }
 
 void CopyOutputRequest::SendResult(scoped_ptr<CopyOutputResult> result) {
   base::ResetAndReturn(&result_callback_).Run(result.Pass());
+  TRACE_EVENT_ASYNC_END0("cc", "CopyOutputRequest", this);
 }
 
 void CopyOutputRequest::SendEmptyResult() {
   SendResult(CopyOutputResult::CreateEmptyResult().Pass());
 }
 
 void CopyOutputRequest::SendBitmapResult(scoped_ptr<SkBitmap> bitmap) {
   SendResult(CopyOutputResult::CreateBitmapResult(bitmap.Pass()).Pass());
 }
 
 void CopyOutputRequest::SendTextureResult(
     const gfx::Size& size,
     const TextureMailbox& texture_mailbox,
     scoped_ptr<SingleReleaseCallback> release_callback) {
   DCHECK(texture_mailbox.IsTexture());
   SendResult(CopyOutputResult::CreateTextureResult(
       size, texture_mailbox, release_callback.Pass()));
 }
 
 void CopyOutputRequest::SetTextureMailbox(
     const TextureMailbox& texture_mailbox) {
   DCHECK(!force_bitmap_result_);
   DCHECK(texture_mailbox.IsTexture());
   has_texture_mailbox_ = true;
   texture_mailbox_ = texture_mailbox;
 }
 
 }  // namespace cc