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..760e0cb4a2e2d2d96e1676b007dba6081d69f07a 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 +301,29 @@ void BrowserWindowCocoa::UpdateTitleBar() {
   NSString* newTitle =
       base::SysUTF16ToNSString(browser_->GetWindowTitleForCurrentTab());
 
+  NSMutableString* titleWithMediaState = [NSMutableString string];

[Robert Sesek, 2015/10/22 00:01:52]

Use [NSMutableString stringWithString:] to avoid unnecessary copying/resizing.

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

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

Can the whitespace char be included in the string resource?  Perhaps it should
be a non-breaking space instead of a plain ASCII space char?  Though, the Cocoa
experts probably know better than me here.  ;-)

+    [titleWithMediaState appendString:@"🔊"];

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

Was this moved to generated_resources.prd?  If so, please upload the updated
patch.

[Robert Sesek, 2015/10/22 00:01:52]

Two appends shouldn't be necessary. Just  [title appendFormat:@"%c <emoji>",
kWhiteSpaceCharacter]

+  }
+  else if (media_state_ ==  TAB_MEDIA_STATE_AUDIO_MUTING) {

[Robert Sesek, 2015/10/22 00:01:52]

nit: this goes on line 310.

+    [titleWithMediaState appendFormat:@"%c", kWhiteSpaceCharacter];
+    [titleWithMediaState appendString:@"🔇"];
+  }
+
   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]