Read compositor VSync information from platform, when possible

ash/display/display_controller.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ash/display/display_controller.h"
 
 #include <algorithm>
 #include <cmath>
 #include <map>
 
@@ skipping 101 matching lines @@
   ui::SetIntProperty(xwindow, kInternalProp, kCARDINAL, internal);
   ui::SetIntProperty(xwindow, kRotationProp, kCARDINAL, xrandr_rotation);
   ui::SetIntProperty(xwindow,
                      kScaleFactorProp,
                      kCARDINAL,
                      100 * display.device_scale_factor());
 #endif
   scoped_ptr<aura::RootWindowTransformer> transformer(
       internal::CreateRootWindowTransformerForDisplay(root->window(), display));
   root->host()->SetRootWindowTransformer(transformer.Pass());
+  gfx::Size resolution;
+  float frame_rate;
+  if (GetDisplayManager()->GetSelectedResolutionForDisplayId(
+          display.id(), &resolution, &frame_rate)) {
+    root->host()->compositor()->OnUpdateVSyncParameters(
+        base::TimeTicks(),
+        base::TimeDelta::FromMicroseconds(frame_rate *
+                                          base::Time::kMicrosecondsPerSecond),
+        true);
+  }
 }
 
 }  // namespace
 
 namespace internal {
 
 // A utility class to store/restore focused/active window
 // when the display configuration has changed.
 class FocusActivationStore {
  public:
@@ skipping 603 matching lines @@
     std::string name =
         root_windows[i] == primary ? "aura_root_0" : "aura_root_x";
     gfx::AcceleratedWidget xwindow =
         root_windows[i]->GetDispatcher()->host()->GetAcceleratedWidget();
     XStoreName(gfx::GetXDisplay(), xwindow, name.c_str());
   }
 #endif
 }
 
 }  // namespace ash