Correctly align tab and toolbar backgrounds with the frame background.

chrome/browser/ui/views/tabs/tab.h

 // 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.
 
 #ifndef CHROME_BROWSER_UI_VIEWS_TABS_TAB_H_
 #define CHROME_BROWSER_UI_VIEWS_TABS_TAB_H_
 
 #include <list>
 #include <string>
 
@@ skipping 136 matching lines @@
 
   // Returns the width for touch tabs.
   static int GetTouchWidth();
 
   // Returns the width for pinned tabs. Pinned tabs always have this width.
   static int GetPinnedWidth();
 
   // Returns the height for immersive mode tabs.
   static int GetImmersiveHeight();
 
+  // Returns the Y offset within the tab background image to begin drawing at
+  // the top of the active tab bounds.  This is a negative value, which will
+  // result in the top of the tab background image being drawn below the top of
+  // the tab.  None of this offset area is actually visible.
+  //
+  // This is necessary for correct vertical alignment of the frame, tab, and
+  // toolbar images with custom themes.
+  static int GetYOffsetForActiveTabBackground();
+
  private:
   friend class TabTest;
   FRIEND_TEST_ALL_PREFIXES(TabTest, CloseButtonLayout);
 
   friend class TabStripTest;
   FRIEND_TEST_ALL_PREFIXES(TabStripTest, TabHitTestMaskWhenStacked);
   FRIEND_TEST_ALL_PREFIXES(TabStripTest, TabCloseButtonVisibilityWhenStacked);
 
   // The animation object used to swap the favicon with the sad tab icon.
   class FaviconCrashAnimation;
@@ skipping 231 matching lines @@
   SkColor button_color_;
 
   // As the majority of the tabs are inactive, and painting tabs is slowish,
   // we cache a handful of the inactive tab backgrounds here.
   static ImageCache* image_cache_;
 
   DISALLOW_COPY_AND_ASSIGN(Tab);
 };
 
 #endif  // CHROME_BROWSER_UI_VIEWS_TABS_TAB_H_