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 7a1b2928a8890ac7d73b46511fa8191782788865..c16c2e70da8d0e32769fc804ffa67b5bf3d15211 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"
@@ -97,6 +98,7 @@ 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) {
   Init();
 }
@@ -117,6 +119,7 @@ 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) {
   Init();
 }
@@ -257,7 +260,9 @@ void Compositor::Draw() {
     // TODO(nduca): Temporary while compositor calls
     // compositeImmediately() directly.
     Layout();
-    host_->Composite(gfx::FrameTime::Now());
+    base::TimeTicks now = gfx::FrameTime::Now();
+    Animate(now);

[piman, 2014/05/23 21:38:56]

nit: in threaded mode, the compositor calls Animate before Layout (I think it
makes sense). Should we do the same for consistency?

[sadrul, 2014/05/23 21:56:11]

Done.

+    host_->Composite(now);
   }
   if (swap_state_ == SWAP_NONE)
     NotifyEnd();
@@ -317,6 +322,12 @@ 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.
@@ -382,6 +393,10 @@ void Compositor::DidAbortSwapBuffers() {
                     OnCompositingAborted(this));
 }
 
+void Compositor::ScheduleAnimationForLayerCollection() {
+  ScheduleAnimation();
+}
+
 const cc::LayerTreeDebugState& Compositor::GetLayerTreeDebugState() const {
   return host_->debug_state();
 }