Let Chrome app handle Ash accelerators first if the app is launched as a window

ash/accelerators/accelerator_controller.cc

Index: ash/accelerators/accelerator_controller.cc
diff --git a/ash/accelerators/accelerator_controller.cc b/ash/accelerators/accelerator_controller.cc
index 91d771e2c444cb7ee006593a3de6ddb4ddca0e62..765b320188106e0be7d4470f76b79137cc5f0059 100644
--- a/ash/accelerators/accelerator_controller.cc
+++ b/ash/accelerators/accelerator_controller.cc
@@ -287,6 +287,11 @@ bool AcceleratorController::Process(const ui::Accelerator& accelerator) {
   return accelerator_manager_->Process(accelerator);
 }
 
+bool AcceleratorController::IsRegistered(
+    const ui::Accelerator& accelerator) const {
+  return accelerator_manager_->GetCurrentTarget(accelerator) != NULL;
+}
+
 void AcceleratorController::SetBrightnessControlDelegate(
     scoped_ptr<BrightnessControlDelegate> brightness_control_delegate) {
   brightness_control_delegate_.swap(brightness_control_delegate);