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

ash/wm/workspace_controller_unittest.cc

Index: ash/wm/workspace_controller_unittest.cc
diff --git a/ash/wm/workspace_controller_unittest.cc b/ash/wm/workspace_controller_unittest.cc
index 7621b28907a124a365f1e40e0887721938e1626f..7cd4535aa1e8faa9cd6e659c51a896741948d242 100644
--- a/ash/wm/workspace_controller_unittest.cc
+++ b/ash/wm/workspace_controller_unittest.cc
@@ -33,6 +33,7 @@
 #include "ui/base/ui_base_types.h"
 #include "ui/compositor/layer.h"
 #include "ui/compositor/scoped_animation_duration_scale_mode.h"
+#include "ui/compositor/test/layer_animator_collection_test_controller.h"
 #include "ui/events/event_utils.h"
 #include "ui/gfx/screen.h"
 #include "ui/views/widget/widget.h"
@@ -1238,6 +1239,9 @@ TEST_F(WorkspaceControllerTest, AnimatedNormToMaxToNormRepositionsRemaining) {
                 desktop_area.width() - window1->bounds().width()) +
             ",32 640x320", window1->bounds().ToString());
   EXPECT_EQ("0,48 256x512", window2->bounds().ToString());
+  ui::LayerAnimatorCollectionTestController collection_controller(
+      window1->layer()->GetCompositor()->layer_animator_collection());
+  collection_controller.StopAllAnimators();
 }
 
 // This tests simulates a browser and an app and verifies the ordering of the