[Mac] Factor out keyboard shortcut handling from ChromeEventProcessingWindow.

ui/views/controls/webview/unhandled_keyboard_event_handler_mac.mm

Index: ui/views/controls/webview/unhandled_keyboard_event_handler_mac.mm
diff --git a/ui/views/controls/webview/unhandled_keyboard_event_handler_mac.mm b/ui/views/controls/webview/unhandled_keyboard_event_handler_mac.mm
index d579c9e34a4ab0321da1c7e4936b21ddb1db3cb0..5fb08006306a37675f7aeb3b8ed2e3514563fbb2 100644
--- a/ui/views/controls/webview/unhandled_keyboard_event_handler_mac.mm
+++ b/ui/views/controls/webview/unhandled_keyboard_event_handler_mac.mm
@@ -4,13 +4,17 @@
 
 #include "ui/views/controls/webview/unhandled_keyboard_event_handler.h"
 
+#import "base/mac/foundation_util.h"
+#import "ui/views/cocoa/native_widget_mac_nswindow.h"
+
 namespace views {
 
 // static
 void UnhandledKeyboardEventHandler::HandleNativeKeyboardEvent(
     gfx::NativeEvent event,
     FocusManager* focus_manager) {
-  NOTIMPLEMENTED();
+  [base::mac::ObjCCastStrict<NativeWidgetMacNSWindow>([event window])
+      redispatchKeyEvent:event];
 }
 
 }  // namespace views