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 0633d12ddd9e000b591adaa4c9dacccc34e2b6bd..031a6b1d9c5d15a107f3938c2bb7249739f78b1c 100644
--- a/ash/display/display_controller.cc
+++ b/ash/display/display_controller.cc
@@ -34,6 +34,7 @@
 #include "ui/aura/window_property.h"
 #include "ui/aura/window_tracker.h"
 #include "ui/compositor/compositor.h"
+#include "ui/compositor/compositor_vsync_manager.h"
 #include "ui/gfx/display.h"
 #include "ui/gfx/screen.h"
 
@@ -120,6 +121,14 @@ 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) &&
+      mode.refresh_rate > 0.0f) {
+    root->host()->compositor()->vsync_manager()->SetAuthoritativeVSyncInterval(
+        base::TimeDelta::FromMicroseconds(base::Time::kMicrosecondsPerSecond /
+                                          mode.refresh_rate));
+  }
 }
 
 }  // namespace