Start using the controller in app's view.

extensions/browser/app_window/native_app_window.h

Index: extensions/browser/app_window/native_app_window.h
diff --git a/extensions/browser/app_window/native_app_window.h b/extensions/browser/app_window/native_app_window.h
index 0bcb65d44f653c66d84062a84e36fd52fc2cd584..9435ce124ebd01e0cf16761a97d9d4fad895adf0 100644
--- a/extensions/browser/app_window/native_app_window.h
+++ b/extensions/browser/app_window/native_app_window.h
@@ -15,6 +15,7 @@
 
 namespace content {
 struct NativeWebKeyboardEvent;
+class WebContents;
 }
 
 namespace extensions {
@@ -58,6 +59,12 @@ class NativeAppWindow : public ui::BaseWindow,
   // switching keys.
   virtual void SetInterceptAllKeys(bool want_all_keys) = 0;
 
+  // Handle key before content receives it.
+  virtual bool PreHandleKeyboardEvent(
+      content::WebContents* source,
+      const content::NativeWebKeyboardEvent& event,
+      bool* is_keyboard_shortcut) = 0;
+
   // Allows the window to handle unhandled keyboard messages coming back from
   // the renderer.
   virtual void HandleKeyboardEvent(