[MacViews] Use ChromeCommandDispatcherDelegate to handle keyboard shortcuts.

ui/views/cocoa/native_widget_mac_nswindow.mm

Index: ui/views/cocoa/native_widget_mac_nswindow.mm
diff --git a/ui/views/cocoa/native_widget_mac_nswindow.mm b/ui/views/cocoa/native_widget_mac_nswindow.mm
index dcd8ea081812e2344391fd9ef1afbb86b7b9b070..1de283fb956b7dc53d180ed36ec06e1e07d4ae91 100644
--- a/ui/views/cocoa/native_widget_mac_nswindow.mm
+++ b/ui/views/cocoa/native_widget_mac_nswindow.mm
@@ -38,6 +38,14 @@
   return self;
 }
 
+// Public methods.
+
+- (void)setCommandDispatcherDelegate:(id<CommandDispatcherDelegate>)delegate {
+  [commandDispatcher_ setDelegate:delegate];
+}
+
+// Private methods.
+
 - (ViewsNSWindowDelegate*)viewsNSWindowDelegate {
   return base::mac::ObjCCastStrict<ViewsNSWindowDelegate>([self delegate]);
 }
@@ -52,6 +60,8 @@
   return menuController && menuController->owner() == [self viewsWidget];
 }
 
+// NSWindow overrides.
+
 - (BOOL)_isTitleHidden {
   if (![self delegate])
     return NO;