CC Animations: Establish AnimationHost, AnimationTimeline and AnimationPlayer

cc/animation/animation_timeline.h

Index: cc/animation/animation_timeline.h
diff --git a/cc/animation/animation_timeline.h b/cc/animation/animation_timeline.h
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index 0000000000000000000000000000000000000000..661f910df1e414c40c09570106a9d71173e8812c
--- /dev/null
+++ b/cc/animation/animation_timeline.h
@@ -0,0 +1,77 @@
+// 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_TIMELINE_H_
+#define CC_ANIMATION_ANIMATION_TIMELINE_H_
+
+#include <vector>
+
+#include "base/containers/hash_tables.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+#include "cc/base/cc_export.h"
+
+namespace cc {
+
+class AnimationHost;
+class AnimationPlayer;
+
+typedef std::vector<scoped_refptr<AnimationPlayer>> AnimationPlayerList;
+
+// An AnimationTimeline owns a group of AnimationPlayers.
+// This is a cc counterpart for blink::AnimationTimeline (in 1:1 relationship).
+// Each AnimationTimeline and it's AnimationPlayers have their copies on
+// the impl thread. We synchronize main thread and impl thread instances
+// using integer IDs.
+class CC_EXPORT AnimationTimeline : public base::RefCounted<AnimationTimeline> {

[Ian Vollick, 2015/05/05 03:52:07]

Why refptr?

[loyso (OOO), 2015/05/05 06:51:18]

Shared between cc::AnimationHost and blink::AnimationTimeline. Same as for
cc::Layer and cc::AnimationPlayer.

[Ian Vollick, 2015/05/07 13:58:43]

IIUC, this means that both the cc::AnimationHost and blink::AnimationTimeline
need to refer to the cc::AnimationTimeline, but we cannot guarantee that the
lifetime of one of these two owners will encompass the lifetime of the other. Is
that true? It seems like the AnimationHost would live longer than any timeline?

[loyso (OOO), 2015/05/08 01:04:35]

Yes, that's true. We can create WebCompositorAnimationTimeline object anywhere
in blink, at any stage. Even if the compositor isn't yet initialized/shut down.

+ public:
+  static scoped_refptr<AnimationTimeline> Create(int id);
+  scoped_refptr<AnimationTimeline> CreateImplInstance() const;
+
+  int id() const { return id_; }
+
+  // Parent AnimationHost.
+  AnimationHost* animation_host() { return animation_host_; }
+  const AnimationHost* animation_host() const { return animation_host_; }
+  void SetAnimationHost(AnimationHost* animation_host);
+
+  void set_is_impl_only(bool is_impl_only) { is_impl_only_ = is_impl_only; }
+  bool is_impl_only() const { return is_impl_only_; }
+
+  void AttachPlayer(AnimationPlayer* player);
+  void DetachPlayer(AnimationPlayer* player);
+
+  void ClearPlayers();
+
+  void PushPropertiesTo(AnimationTimeline* timeline_impl);
+
+  AnimationPlayer* GetPlayerById(int player_id) const;
+
+ private:
+  friend class base::RefCounted<AnimationTimeline>;
+
+  explicit AnimationTimeline(int id);
+  virtual ~AnimationTimeline();
+
+  void PushAttachedPlayersToImplThread(AnimationTimeline* timeline) const;
+  void RemoveDetachedPlayersFromImplThread(AnimationTimeline* timeline) const;
+  void PushPropertiesToImplThread(AnimationTimeline* timeline);
+
+  void ErasePlayers(AnimationPlayerList::iterator begin,
+                    AnimationPlayerList::iterator end);
+
+  AnimationPlayerList players_;
+  int id_;
+  AnimationHost* animation_host_;
+
+  // Impl-only AnimationTimeline has no main thread instance and lives on
+  // it's own.
+  bool is_impl_only_;
+
+  DISALLOW_COPY_AND_ASSIGN(AnimationTimeline);
+};
+
+}  // namespace cc
+
+#endif  // CC_ANIMATION_ANIMATION_TIMELINE_H_