Indicate in the Window menu which Chrome window has an active sound playing

chrome/browser/ui/cocoa/browser_window_controller.mm

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #import "chrome/browser/ui/cocoa/browser_window_controller.h"
 
 #include <cmath>
 #include <numeric>
 
 #include "base/command_line.h"
@@ skipping 1877 matching lines @@
 
 - (void)executeExtensionCommand:(const std::string&)extension_id
                         command:(const extensions::Command&)command {
   // Global commands are handled by the ExtensionCommandsGlobalRegistry
   // instance.
   DCHECK(!command.global());
   extension_keybinding_registry_->ExecuteCommand(extension_id,
                                                  command.accelerator());
 }
 
+- (void)setMediaState:(TabMediaState)mediaState {
+  [self browserWindow]->UpdateMediaState(mediaState);

[miu, 2015/10/21 20:06:52]

Rather than declare the UpdateMediaState() method in the cross-platform
BrowserWindow interface class (see comment above), you could just:

  static_cast<BrowserWindowCocoa*>([self
browserWindow])->UpdateMediaState(mediaState);

+}
+
 @end  // @implementation BrowserWindowController
 
 @implementation BrowserWindowController(Fullscreen)
 
 - (void)handleLionToggleFullscreen {
   DCHECK(base::mac::IsOSLionOrLater());
   chrome::ExecuteCommand(browser_.get(), IDC_FULLSCREEN);
 }
 
 - (void)enterBrowserFullscreenWithToolbar:(BOOL)withToolbar {
@@ skipping 152 matching lines @@
 
 - (BOOL)supportsBookmarkBar {
   return [self supportsWindowFeature:Browser::FEATURE_BOOKMARKBAR];
 }
 
 - (BOOL)isTabbedWindow {
   return browser_->is_type_tabbed();
 }
 
 @end  // @implementation BrowserWindowController(WindowType)