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

ui/compositor/compositor.cc

Index: ui/compositor/compositor.cc
diff --git a/ui/compositor/compositor.cc b/ui/compositor/compositor.cc
index 325425cf47d40fce656615e85fdb60a1e79f7401..b511e6d2eb460b562b247db1f12105415607fef1 100644
--- a/ui/compositor/compositor.cc
+++ b/ui/compositor/compositor.cc
@@ -26,6 +26,7 @@
 #include "ui/compositor/compositor_vsync_manager.h"
 #include "ui/compositor/dip_util.h"
 #include "ui/compositor/layer.h"
+#include "ui/compositor/layer_animator_collection.h"
 #include "ui/gfx/frame_time.h"
 #include "ui/gl/gl_context.h"
 #include "ui/gl/gl_switches.h"
@@ -84,6 +85,7 @@ Compositor::Compositor(gfx::AcceleratedWidget widget,
       waiting_on_compositing_end_(false),
       draw_on_compositing_end_(false),
       swap_state_(SWAP_NONE),
+      layer_animator_collection_(this),
       schedule_draw_factory_(this) {
   root_web_layer_ = cc::Layer::Create();
   root_web_layer_->SetAnchorPoint(gfx::PointF(0.f, 0.f));
@@ -217,8 +219,10 @@ void Compositor::Draw() {
   if (!IsLocked()) {
     // TODO(nduca): Temporary while compositor calls
     // compositeImmediately() directly.
+    base::TimeTicks now = gfx::FrameTime::Now();
+    Animate(now);
     Layout();
-    host_->Composite(gfx::FrameTime::Now());
+    host_->Composite(now);
   }
   if (swap_state_ == SWAP_NONE)
     NotifyEnd();
@@ -278,6 +282,12 @@ bool Compositor::HasObserver(CompositorObserver* observer) {
   return observer_list_.HasObserver(observer);
 }
 
+void Compositor::Animate(base::TimeTicks frame_begin_time) {
+  layer_animator_collection_.Progress(frame_begin_time);
+  if (layer_animator_collection_.HasActiveAnimators())
+    host_->SetNeedsAnimate();
+}
+
 void Compositor::Layout() {
   // We're sending damage that will be addressed during this composite
   // cycle, so we don't need to schedule another composite to address it.
@@ -343,6 +353,10 @@ void Compositor::DidAbortSwapBuffers() {
                     OnCompositingAborted(this));
 }
 
+void Compositor::ScheduleAnimationForLayerCollection() {
+  host_->SetNeedsAnimate();
+}
+
 const cc::LayerTreeDebugState& Compositor::GetLayerTreeDebugState() const {
   return host_->debug_state();
 }