cc: Animations committed together should start together

This change makes newly-committed animations wait for tree
activation before they're able to affect the active tree, and
makes newly-deleted animations wait for tree activation before
they no longer affect the active tree. This is accomplished by
tracking whether each animation affects active observers,
inactive (pending) observers, or both.

As a result, animations committed together will start
together, after the next activation.

BUG=225643

Review URL: https://codereview.chromium.org/259043004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@267269 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 24 insertions, 0 deletions

diff --git a/cc/animation/animation.h b/cc/animation/animation.h
index 3cfc8bb..ecc48b5 100644
--- a/cc/animation/animation.h
+++ b/cc/animation/animation.h
@@ -126,6 +126,16 @@ class CC_EXPORT Animation {
   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 set_affects_active_observers(bool affects_active_observers) {
+    affects_active_observers_ = affects_active_observers;
+  }
+  bool affects_active_observers() const { return affects_active_observers_; }
+
+  void set_affects_pending_observers(bool affects_pending_observers) {
+    affects_pending_observers_ = affects_pending_observers;
+  }
+  bool affects_pending_observers() const { return affects_pending_observers_; }
+
  private:
   Animation(scoped_ptr<AnimationCurve> curve,
             int animation_id,
@@ -182,6 +192,20 @@ class CC_EXPORT Animation {
 
   bool is_impl_only_;
 
+  // When pushed from a main-thread controller to a compositor-thread
+  // controller, an animation will initially only affect pending observers
+  // (corresponding to layers in the pending tree). Animations that only
+  // affect pending observers are able to reach the Starting state and tick
+  // pending observers, but cannot proceed any further and do not tick active
+  // observers. After activation, such animations affect both kinds of observers
+  // and are able to proceed past the Starting state. When the removal of
+  // an animation is pushed from a main-thread controller to a
+  // compositor-thread controller, this initially only makes the animation
+  // stop affecting pending observers. After activation, such animations no
+  // longer affect any observers, and are deleted.
+  bool affects_active_observers_;
+  bool affects_pending_observers_;
+
   DISALLOW_COPY_AND_ASSIGN(Animation);
 };