Improvements to tab title prefix eliding as per email discussions.

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

 // Copyright (c) 2011 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.
 
 #include "base/mac/mac_util.h"
 #import "chrome/browser/themes/theme_service.h"
 #import "chrome/browser/ui/cocoa/menu_controller.h"
 #import "chrome/browser/ui/cocoa/tabs/tab_controller.h"
 #import "chrome/browser/ui/cocoa/tabs/tab_controller_target.h"
 #import "chrome/browser/ui/cocoa/tabs/tab_view.h"
 #import "chrome/browser/ui/cocoa/themed_window.h"
+#include "chrome/browser/ui/title_prefix_matcher.h"
 #import "chrome/common/extensions/extension.h"
 #include "grit/generated_resources.h"
 #import "third_party/GTM/AppKit/GTMFadeTruncatingTextFieldCell.h"
 #include "ui/base/l10n/l10n_util_mac.h"
 
 @implementation TabController
 
 @synthesize action = action_;
 @synthesize app = app_;
 @synthesize loadingState = loadingState_;
 @synthesize mini = mini_;
 @synthesize pinned = pinned_;
 @synthesize target = target_;
+@synthesize url = url_;
 @synthesize iconView = iconView_;
 @synthesize titleView = titleView_;
 @synthesize closeButton = closeButton_;
 
 namespace TabControllerInternal {
 
 // A C++ delegate that handles enabling/disabling menu items and handling when
 // a menu command is chosen. Also fixes up the menu item label for "pin/unpin
 // tab".
 class MenuDelegate : public ui::SimpleMenuModel::Delegate {
@@ skipping 266 matching lines @@
     return [[self target] performSelector:@selector(inRapidClosureMode)] ?
         YES : NO;
   }
   return NO;
 }
 
 - (void)setTitleCommonPrefixLength:(NSUInteger)length {
   DCHECK([[titleView_ cell] isKindOfClass:
       [GTMFadeTruncatingTextFieldCell class]]);
   GTMFadeTruncatingTextFieldCell* cell = [titleView_ cell];
-  [cell setDesiredCharactersToTruncateFromHead:length];
-  [cell setTruncateMode:length > 0 ? GTMFadeTruncatingHeadAndTail :
-                                     GTMFadeTruncatingTail];
+  [cell setDesiredCharactersToTruncateFromHead:length -
+      TitlePrefixMatcher::kCommonCharsToShow];
+  [cell setTruncateMode:length > TitlePrefixMatcher::kMinElidingLength ?
+      GTMFadeTruncatingHeadAndTail : GTMFadeTruncatingTail];
 }
 
 @end