Thread ui transform animations

ui/aura/root_window.cc

Index: ui/aura/root_window.cc
diff --git a/ui/aura/root_window.cc b/ui/aura/root_window.cc
index 7ff474f23f7a43b4abc033c9a8b640e1c28af8c1..68de1bf5bfd0bfe3634d5e376227a5fdea20e854 100644
--- a/ui/aura/root_window.cc
+++ b/ui/aura/root_window.cc
@@ -430,6 +430,10 @@ gfx::Point RootWindow::GetLastMouseLocationInRoot() const {
   return location;
 }
 
+void RootWindow::DelayDrawsForTesting(base::TimeDelta delay) {
+  draw_scheduling_delay_for_testing_ = delay;
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // RootWindow, Window overrides:
 
@@ -463,11 +467,19 @@ ui::EventTarget* RootWindow::GetParentTarget() {
 // RootWindow, ui::CompositorDelegate implementation:
 
 void RootWindow::ScheduleDraw() {
-  if (!defer_draw_scheduling_) {
-    defer_draw_scheduling_ = true;
+  if (defer_draw_scheduling_)
+    return;
+
+  defer_draw_scheduling_ = true;
+  if (draw_scheduling_delay_for_testing_ == base::TimeDelta()) {
     MessageLoop::current()->PostTask(
         FROM_HERE,
         base::Bind(&RootWindow::Draw, schedule_paint_factory_.GetWeakPtr()));
+  } else {
+    MessageLoop::current()->PostDelayedTask(
+        FROM_HERE,
+        base::Bind(&RootWindow::Draw, schedule_paint_factory_.GetWeakPtr()),
+        draw_scheduling_delay_for_testing_);
   }
 }