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

chrome/browser/ui/cocoa/browser_window_cocoa.mm

Index: chrome/browser/ui/cocoa/browser_window_cocoa.mm
diff --git a/chrome/browser/ui/cocoa/browser_window_cocoa.mm b/chrome/browser/ui/cocoa/browser_window_cocoa.mm
index 028c744d53dd56751ccc7c2e29262a534a056ffc..3b2a55f18ebbceef7ab1ff4cc58cbee980be58b2 100644
--- a/chrome/browser/ui/cocoa/browser_window_cocoa.mm
+++ b/chrome/browser/ui/cocoa/browser_window_cocoa.mm
@@ -88,6 +88,8 @@ const int kBookmarkAppBubbleViewHeight = 46;
 
 const int kIconPreviewTargetSize = 128;
 
+const char kWhiteSpaceCharacter = ' ';
+
 base::string16 TrimText(NSString* controlText) {
   base::string16 text = base::SysNSStringToUTF16(controlText);
   base::TrimWhitespace(text, base::TRIM_ALL, &text);
@@ -299,12 +301,25 @@ void BrowserWindowCocoa::UpdateTitleBar() {
   NSString* newTitle =
       base::SysUTF16ToNSString(browser_->GetWindowTitleForCurrentTab());
 
+  NSMutableString* titleWithMediaState = [NSMutableString
+                                         stringWithString:newTitle];

[Robert Sesek, 2015/10/23 14:26:37]

There's no reason to not keep |newTitle| around at all now. You can just do,

NSString* newTitle = [NSMutableString stringWithString:
    base::SysUTF16ToNSString(browser_->GetWindowTitleForCurrentTab()];

+
+  if (media_state_ == TAB_MEDIA_STATE_AUDIO_PLAYING)
+    [titleWithMediaState appendFormat:@"%c 🔊", kWhiteSpaceCharacter];

[Robert Sesek, 2015/10/23 14:26:37]

There's now the %c whitespace character that's being formatted, as well as an
additional space in the format string. Is that intentional?

+  else if (media_state_ ==  TAB_MEDIA_STATE_AUDIO_MUTING)

[Robert Sesek, 2015/10/23 14:26:37]

nit: extra space after ==

+    [titleWithMediaState appendFormat:@"%c 🔇", kWhiteSpaceCharacter];
+
   pending_window_title_.reset(
       [BrowserWindowUtils scheduleReplaceOldTitle:pending_window_title_.get()
-                                     withNewTitle:newTitle
+                                     withNewTitle:titleWithMediaState
                                         forWindow:window()]);
 }
 
+void BrowserWindowCocoa::UpdateMediaState(TabMediaState media_state) {
+  media_state_ = media_state;
+  UpdateTitleBar();
+}
+
 void BrowserWindowCocoa::BookmarkBarStateChanged(
     BookmarkBar::AnimateChangeType change_type) {
   [[controller_ bookmarkBarController]