Add impl/comp scrolling instrumentation.

cc/layers/layer.cc

 // Copyright 2010 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/layers/layer.h"
 
 #include <algorithm>
 
+#include "base/debug/trace_event.h"
 #include "base/location.h"
 #include "base/metrics/histogram.h"
 #include "base/single_thread_task_runner.h"
 #include "cc/animation/animation.h"
 #include "cc/animation/animation_events.h"
 #include "cc/animation/layer_animation_controller.h"
 #include "cc/layers/layer_impl.h"
 #include "cc/output/copy_output_request.h"
 #include "cc/output/copy_output_result.h"
 #include "cc/trees/layer_tree_host.h"
@@ skipping 537 matching lines @@
 }
 
 bool Layer::TransformIsAnimating() const {
   return layer_animation_controller_->IsAnimatingProperty(Animation::Transform);
 }
 
 void Layer::SetScrollOffset(gfx::Vector2d scroll_offset) {
   DCHECK(IsPropertyChangeAllowed());
   if (scroll_offset_ == scroll_offset)
     return;
+  TRACE_EVENT2("impl-scroll",
+               "Layer::SetScrollOffset",
+               "scroll_x", scroll_offset.x(),
+               "scroll_y", scroll_offset.y());
   scroll_offset_ = scroll_offset;
   SetNeedsCommit();
 }
 
 void Layer::SetScrollOffsetFromImplSide(gfx::Vector2d scroll_offset) {
   DCHECK(IsPropertyChangeAllowed());
   // This function only gets called during a begin frame, so there
   // is no need to call SetNeedsUpdate here.
   DCHECK(layer_tree_host_ && layer_tree_host_->CommitRequested());
   if (scroll_offset_ == scroll_offset)
     return;
+  TRACE_EVENT2("impl-scroll",
+               "Layer::SetScrollOffsetFromImplSide",
+               "scroll_x", scroll_offset.x(),
+               "scroll_y", scroll_offset.y());
   scroll_offset_ = scroll_offset;
   SetNeedsPushProperties();
   if (!did_scroll_callback_.is_null())
     did_scroll_callback_.Run();
   // The callback could potentially change the layer structure:
   // "this" may have been destroyed during the process.
 }
 
 void Layer::SetMaxScrollOffset(gfx::Vector2d max_scroll_offset) {
   DCHECK(IsPropertyChangeAllowed());
@@ skipping 386 matching lines @@
 
 RenderingStatsInstrumentation* Layer::rendering_stats_instrumentation() const {
   return layer_tree_host_->rendering_stats_instrumentation();
 }
 
 bool Layer::SupportsLCDText() const {
   return false;
 }
 
 }  // namespace cc