CC Animation: Use unordered_map instead of vector.

cc/animation/animation_host.h

 // Copyright 2015 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_ANIMATION_ANIMATION_HOST_H_
 #define CC_ANIMATION_ANIMATION_HOST_H_
 
 #include <unordered_map>
-#include <vector>
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/time/time.h"
 #include "cc/animation/animation.h"
 #include "cc/base/cc_export.h"
 #include "cc/trees/mutator_host_client.h"
 #include "ui/gfx/geometry/box_f.h"
 #include "ui/gfx/geometry/vector2d_f.h"
 
 namespace gfx {
 class ScrollOffset;
 }
 
 namespace cc {
 
 class AnimationEvents;
 class AnimationPlayer;
 class AnimationRegistrar;
 class AnimationTimeline;
 class ElementAnimations;
 class LayerAnimationController;
 class LayerTreeHost;
 
 enum class ThreadInstance { MAIN, IMPL };
 
-typedef std::vector<scoped_refptr<AnimationTimeline>> AnimationTimelineList;
-
 // An AnimationHost contains all the state required to play animations.
 // Specifically, it owns all the AnimationTimelines objects.
 // There is just one AnimationHost for LayerTreeHost on main renderer thread
 // and just one AnimationHost for LayerTreeHostImpl on impl thread.
 // We synchronize them during the commit process in a one-way data flow process
 // (PushPropertiesTo).
 // An AnimationHost talks to its correspondent LayerTreeHost via
 // LayerTreeMutatorsClient interface.
 // AnimationHost has it's own instance of AnimationRegistrar,
 // we want to merge AnimationRegistrar into AnimationHost.
@@ skipping 105 matching lines @@
 
   void ScrollAnimationAbort(bool needs_completion);
 
  private:
   explicit AnimationHost(ThreadInstance thread_instance);
 
   void PushTimelinesToImplThread(AnimationHost* host_impl) const;
   void RemoveTimelinesFromImplThread(AnimationHost* host_impl) const;
   void PushPropertiesToImplThread(AnimationHost* host_impl);
 
-  void EraseTimelines(AnimationTimelineList::iterator begin,
-                      AnimationTimelineList::iterator end);
+  void EraseTimeline(scoped_refptr<AnimationTimeline> timeline);
 
   // TODO(loyso): For now AnimationPlayers share LayerAnimationController object
   // if they are attached to the same element(layer). Note that Element can
   // contain many Layers.
   using LayerToElementAnimationsMap =
       std::unordered_map<int, scoped_ptr<ElementAnimations>>;
   LayerToElementAnimationsMap layer_to_element_animations_map_;
 
-  AnimationTimelineList timelines_;
+  // A list of all timelines which this host owns.
+  using IdToTimelineMap =
+      std::unordered_map<int, scoped_refptr<AnimationTimeline>>;
+  IdToTimelineMap id_to_timeline_map_;
+
   scoped_ptr<AnimationRegistrar> animation_registrar_;
   MutatorHostClient* mutator_host_client_;
 
   class ScrollOffsetAnimations;
   scoped_ptr<ScrollOffsetAnimations> scroll_offset_animations_;
 
   const ThreadInstance thread_instance_;
 
   DISALLOW_COPY_AND_ASSIGN(AnimationHost);
 };
 
 }  // namespace cc
 
 #endif  // CC_ANIMATION_ANIMATION_HOST_H_