Add synthetic delay testing framework

cc/trees/thread_proxy.cc

 // Copyright 2011 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/trees/thread_proxy.h"
 
 #include <string>
 
 #include "base/auto_reset.h"
 #include "base/bind.h"
+#include "base/debug/synthetic_delay.h"
 #include "base/debug/trace_event.h"
 #include "base/metrics/histogram.h"
 #include "cc/debug/benchmark_instrumentation.h"
 #include "cc/input/input_handler.h"
 #include "cc/output/context_provider.h"
 #include "cc/output/output_surface.h"
 #include "cc/quads/draw_quad.h"
 #include "cc/resources/prioritized_resource_manager.h"
 #include "cc/scheduler/delay_based_time_source.h"
 #include "cc/scheduler/frame_rate_controller.h"
@@ skipping 998 matching lines @@
   Proxy::MainThreadTaskRunner()->PostTask(
       FROM_HERE,
       base::Bind(&ThreadProxy::CreateAndInitializeOutputSurface,
                  main_thread_weak_ptr_));
 }
 
 DrawSwapReadbackResult ThreadProxy::DrawSwapReadbackInternal(
     bool forced_draw,
     bool swap_requested,
     bool readback_requested) {
+  SYNTHETIC_DELAY("cc.draw_and_swap");
   DrawSwapReadbackResult result;
   result.did_draw = false;
   result.did_swap = false;
   result.did_readback = false;
   DCHECK(IsImplThread());
   DCHECK(layer_tree_host_impl_.get());
   if (!layer_tree_host_impl_)
     return result;
 
   DCHECK(layer_tree_host_impl_->renderer());
@@ skipping 546 matching lines @@
     completion_event_for_commit_held_on_tree_activation_ = NULL;
   }
 
   UpdateBackgroundAnimateTicking();
 
   commit_to_activate_duration_history_.InsertSample(
       base::TimeTicks::HighResNow() - commit_complete_time_);
 }
 
 }  // namespace cc