compositor: Tick the UI animations from cc, instead of from timer callbacks.

ui/compositor/layer_animator.cc

Index: ui/compositor/layer_animator.cc
diff --git a/ui/compositor/layer_animator.cc b/ui/compositor/layer_animator.cc
index ce2b0ff364d9d7b5150ba90fa8879c5f8f46cc04..67c418aa082a0ca852cc2644a4d70269f145ee62 100644
--- a/ui/compositor/layer_animator.cc
+++ b/ui/compositor/layer_animator.cc
@@ -14,7 +14,7 @@
 #include "ui/compositor/layer_animation_delegate.h"
 #include "ui/compositor/layer_animation_observer.h"
 #include "ui/compositor/layer_animation_sequence.h"
-#include "ui/gfx/animation/animation_container.h"
+#include "ui/compositor/layer_animator_collection.h"
 #include "ui/gfx/frame_time.h"
 
 #define SAFE_INVOKE_VOID(function, running_anim, ...) \
@@ -31,22 +31,9 @@
 
 namespace ui {
 
-class LayerAnimator;
-
 namespace {
 
 const int kDefaultTransitionDurationMs = 120;
-const int kTimerIntervalMs = 10;
-
-// Returns the AnimationContainer we're added to.
-gfx::AnimationContainer* GetAnimationContainer() {
-  static gfx::AnimationContainer* container = NULL;
-  if (!container) {
-    container = new gfx::AnimationContainer();
-    container->AddRef();
-  }
-  return container;
-}
 
 }  // namespace
 
@@ -181,8 +168,10 @@ void LayerAnimator::StartTogether(
 
   adding_animations_ = true;
   if (!is_animating()) {
-    if (GetAnimationContainer()->is_running())
-      last_step_time_ = GetAnimationContainer()->last_tick_time();
+    LayerAnimatorCollection* collection =
+        LayerAnimatorCollection::GetInstance();
+    if (collection->HasActiveAnimators())
+      last_step_time_ = collection->last_tick_time();
     else
       last_step_time_ = gfx::FrameTime::Now();
   }
@@ -395,14 +384,6 @@ void LayerAnimator::Step(base::TimeTicks now) {
   }
 }
 
-void LayerAnimator::SetStartTime(base::TimeTicks start_time) {
-  // Do nothing.
-}
-
-base::TimeDelta LayerAnimator::GetTimerInterval() const {
-  return base::TimeDelta::FromMilliseconds(kTimerIntervalMs);
-}
-
 void LayerAnimator::StopAnimatingInternal(bool abort) {
   scoped_refptr<LayerAnimator> retain(this);
   while (is_animating()) {
@@ -432,9 +413,9 @@ void LayerAnimator::UpdateAnimationState() {
 
   const bool should_start = is_animating();
   if (should_start && !is_started_)
-    GetAnimationContainer()->Start(this);
+    LayerAnimatorCollection::GetInstance()->StartAnimator(this);
   else if (!should_start && is_started_)
-    GetAnimationContainer()->Stop(this);
+    LayerAnimatorCollection::GetInstance()->StopAnimator(this);
 
   is_started_ = should_start;
 }
@@ -753,14 +734,14 @@ bool LayerAnimator::StartSequenceImmediately(LayerAnimationSequence* sequence) {
   // a resolution that can be as bad as 15ms. If this causes glitches in the
   // animations, this can be switched to HighResNow() (animation uses Now()
   // internally).
-  // All LayerAnimators share the same AnimationContainer. Use the
+  // All LayerAnimators share the same LayerAnimatorCollection. Use the
   // last_tick_time() from there to ensure animations started during the same
   // event complete at the same time.
   base::TimeTicks start_time;
   if (is_animating() || adding_animations_)
     start_time = last_step_time_;
-  else if (GetAnimationContainer()->is_running())
-    start_time = GetAnimationContainer()->last_tick_time();
+  else if (LayerAnimatorCollection::GetInstance()->HasActiveAnimators())
+    start_time = LayerAnimatorCollection::GetInstance()->last_tick_time();

[ajuma, 2014/05/23 17:10:00]

It's possible for LayerAnimatorCollection to have active animators, but to have
an old last_tick_time (e.g. suppose we just added another animator to the
collection, but Progress hasn't been called yet). One fix would be for
LayerAnimatorCollection::StartAnimator to set last_tick_time to
gfx::FrameTime::Now() if the collection was previously empty. (It would also be
good to have a unit test that verifies that
LayerAnimationCollection::last_tick_time gets updated in this situation.)

[sadrul, 2014/05/23 18:02:42]

Done.

   else
     start_time = gfx::FrameTime::Now();