Adds constants and runner for animations

services/view_manager/animation_runner.h

+// Copyright 2014 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 SERVICES_VIEW_MANAGER_ANIMATION_RUNNER_H_
+#define SERVICES_VIEW_MANAGER_ANIMATION_RUNNER_H_
+
+#include "base/containers/scoped_ptr_hash_map.h"
+#include "base/observer_list.h"
+#include "base/time/time.h"
+
+namespace mojo {
+
+class AnimationGroup;
+
+namespace service {
+
+class AnimationRunnerObserver;
+class ScheduledAnimationGroup;
+class ServerView;
+
+// AnimationRunner is responsible for maintaing and running a set of animations.
+// The animations are represented as a set of AnimationGroups. New animations
+// are scheduled by way of Schedule(). A |view| may only have one animation
+// running at a time. Schedule()ing a new animation implicitly cancels the
+// outstanding animation. Animations progress by way of the Tick() function.
+class AnimationRunner {
+ public:
+  explicit AnimationRunner(base::TimeTicks now);
+  ~AnimationRunner();
+
+  void AddObserver(AnimationRunnerObserver* observer);
+  void RemoveObserver(AnimationRunnerObserver* observer);
+
+  // Schedules an animation for |view|. If there is an existing animation in
+  // progress for |view| it is canceled and any properties that were animating
+  // but are no longer animating are set to their target value.
+  // Returns 0 if |transport_group| is not valid.
+  uint32_t Schedule(ServerView* view, const AnimationGroup& transport_group);
+
+  // Returns the view the animation identified by |id| was scheduled for.
+  ServerView* GetViewForAnimation(uint32_t id);
+
+  // Cancels the animation scheduled for |view|. Does nothing if there is no
+  // animation scheduled for |view|. This does not change |view|. That is, any
+  // in progress animations are stopped.
+  void CancelAnimationForView(ServerView* view);
+
+  // Advance the animations updating values appropriately.
+  void Tick(base::TimeTicks time);
+
+  // Returns true if there are animations currently scheduled.
+  bool HasAnimations() const { return !animation_map_.empty(); }
+
+ private:
+  using ViewAnimationMap =
+      base::ScopedPtrHashMap<ServerView*, ScheduledAnimationGroup>;
+
+  uint32_t next_id_;
+
+  base::TimeTicks last_tick_time_;
+
+  ObserverList<AnimationRunnerObserver> observers_;
+
+  ViewAnimationMap animation_map_;
+
+  DISALLOW_COPY_AND_ASSIGN(AnimationRunner);
+};
+
+}  // namespace service
+}  // namespace mojo
+
+#endif  // SERVICES_VIEW_MANAGER_ANIMATION_RUNNER_H_