Make tab tooltip behavior consistent across all desktop platforms.

chrome/browser/ui/cocoa/tabs/tab_strip_controller.mm

 // Copyright (c) 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/tabs/tab_strip_controller.h"
 
 #import <QuartzCore/QuartzCore.h>
 
 #include <cmath>
 #include <limits>
@@ skipping 1205 matching lines @@
   [self layoutTabsWithAnimation:initialLayoutComplete_ regenerateSubviews:YES];
 }
 
 - (void)layoutTabsWithoutAnimation {
   [self layoutTabsWithAnimation:NO regenerateSubviews:YES];
 }
 
 // Handles setting the title of the tab based on the given |contents|. Uses
 // a canned string if |contents| is NULL.
 - (void)setTabTitle:(TabController*)tab withContents:(WebContents*)contents {
-  // TODO(miu): Rectify inconsistent tooltip behavior.  http://crbug.com/310947
-
   base::string16 title;
   if (contents)
     title = contents->GetTitle();
   if (title.empty())
     title = l10n_util::GetStringUTF16(IDS_BROWSER_WINDOW_MAC_TAB_UNTITLED);
   [tab setTitle:base::SysUTF16ToNSString(title)];
 
   const base::string16& toolTip = chrome::AssembleTabTooltipText(
       title, chrome::GetTabMediaStateForContents(contents));
   [tab setToolTip:base::SysUTF16ToNSString(toolTip)];
@@ skipping 979 matching lines @@
 NSView* GetSheetParentViewForWebContents(WebContents* web_contents) {
   // View hierarchy of the contents view:
   // NSView  -- switchView, same for all tabs
   // +- NSView  -- TabContentsController's view
   //    +- TabContentsViewCocoa
   //
   // Changing it? Do not forget to modify
   // -[TabStripController swapInTabAtIndex:] too.
   return [web_contents->GetView()->GetNativeView() superview];
 }