Use LatencyInfoSwapPromise to track LatencyInfo through compositor

cc/trees/layer_tree_impl.h

 // Copyright 2012 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.
 
 #ifndef CC_TREES_LAYER_TREE_IMPL_H_
 #define CC_TREES_LAYER_TREE_IMPL_H_
 
 #include <list>
 #include <string>
 #include <vector>
 
 #include "base/containers/hash_tables.h"
 #include "base/values.h"
 #include "cc/base/scoped_ptr_vector.h"
 #include "cc/base/swap_promise.h"
 #include "cc/layers/layer_impl.h"
 #include "cc/resources/ui_resource_client.h"
-#include "ui/events/latency_info.h"
 
 #if defined(COMPILER_GCC)
 namespace BASE_HASH_NAMESPACE {
 template<>
 struct hash<cc::LayerImpl*> {
   size_t operator()(cc::LayerImpl* ptr) const {
     return hash<size_t>()(reinterpret_cast<size_t>(ptr));
   }
 };
 }  // namespace BASE_HASH_NAMESPACE
@@ skipping 171 matching lines @@
   bool ViewportSizeInvalid() const;
   void SetViewportSizeInvalid();
   void ResetViewportSizeInvalid();
 
   // Useful for debug assertions, probably shouldn't be used for anything else.
   Proxy* proxy() const;
 
   void SetRootLayerScrollOffsetDelegate(
       LayerScrollOffsetDelegate* root_layer_scroll_offset_delegate);
 
-  void SetLatencyInfo(const ui::LatencyInfo& latency_info);
-  const ui::LatencyInfo& GetLatencyInfo();
-  void ClearLatencyInfo();
+  void TakeLatencyInfo(ui::LatencyInfo* latency_info);
 
   // Call this function when you expect there to be a swap buffer.
   // See swap_promise.h for how to use SwapPromise.
   // LayerTreeImpl will take the ownershipf of |swap_promise|.
   void QueueSwapPromise(scoped_ptr<SwapPromise> swap_promise);
 
   // Take the |new_swap_promise| and appended it to |swap_promise_list_|.
   void PassSwapPromises(ScopedPtrVector<SwapPromise>* new_swap_promise);
   void FinishSwapPromises();
   void BreakSwapPromises(SwapPromise::DidNotSwapReason reason);
@@ skipping 51 matching lines @@
   bool contents_textures_purged_;
   bool viewport_size_invalid_;
   bool needs_update_draw_properties_;
 
   // In impl-side painting mode, this is true when the tree may contain
   // structural differences relative to the active tree.
   bool needs_full_tree_sync_;
 
   bool next_activation_forces_redraw_;
 
-  ui::LatencyInfo latency_info_;
-
   ScopedPtrVector<SwapPromise> swap_promise_list_;
 
   UIResourceRequestQueue ui_resource_request_queue_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(LayerTreeImpl);
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_LAYER_TREE_IMPL_H_