Add app.dock.setMenu API

atom/browser/mac/atom_application_delegate.mm

@@ -10,6 +10,16 @@
 
 @implementation AtomApplicationDelegate
 
+- (id)init {
+  self = [super init];
+  menu_controller_.reset([[AtomMenuController alloc] init]);
+  return self;
+}
+
+- (void)setApplicationDockMenu:(ui::MenuModel*)model {
+  [menu_controller_ populateWithModel:model];
+}
+
 - (void)applicationWillFinishLaunching:(NSNotification*)notify {
   atom::Browser::Get()->WillFinishLaunching();
 }
@@ -18,6 +28,10 @@
   atom::Browser::Get()->DidFinishLaunching();
 }
 
+- (NSMenu*)applicationDockMenu:(NSApplication*)sender {
+  return [menu_controller_ menu];
+}
+
 - (BOOL)application:(NSApplication*)sender
            openFile:(NSString*)filename {
   std::string filename_str(base::SysNSStringToUTF8(filename));