Read compositor VSync information from platform, when possible

ash/display/display_controller.cc

Index: ash/display/display_controller.cc
diff --git a/ash/display/display_controller.cc b/ash/display/display_controller.cc
index 7b7cc5882e5592a336e718a28d2fa3c442bb5215..c4877a92ca4fa2866bd39e02653bd16b1147d571 100644
--- a/ash/display/display_controller.cc
+++ b/ash/display/display_controller.cc
@@ -119,6 +119,15 @@ void SetDisplayPropertiesOnHostWindow(aura::RootWindow* root,
   scoped_ptr<aura::RootWindowTransformer> transformer(
       internal::CreateRootWindowTransformerForDisplay(root->window(), display));
   root->host()->SetRootWindowTransformer(transformer.Pass());
+
+  internal::DisplayMode mode;
+  if (GetDisplayManager()->GetSelectedModeForDisplayId(display.id(), &mode)) {
+    root->host()->compositor()->OnUpdateVSyncParameters(
+        base::TimeTicks(),
+        base::TimeDelta::FromMicroseconds(mode.refresh_rate *
+                                          base::Time::kMicrosecondsPerSecond),
+        true);
+  }
 }
 
 }  // namespace