Fix the misalignment on CrOS of the tab background images

chrome/browser/ui/gtk/tabs/tab_renderer_gtk.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_GTK_TABS_TAB_RENDERER_GTK_H_
 #define CHROME_BROWSER_UI_GTK_TABS_TAB_RENDERER_GTK_H_
 
 #include <gtk/gtk.h>
 #include <map>
 
@@ skipping 295 matching lines @@
   void PaintTab(GtkWidget* widget, GdkEventExpose* event);
 
   // Paint various portions of the Tab
   void PaintTitle(GtkWidget* widget, cairo_t* cr);
   void PaintIcon(GtkWidget* widget, cairo_t* cr);
   void PaintTabBackground(GtkWidget* widget, cairo_t* cr);
   void PaintInactiveTabBackground(GtkWidget* widget, cairo_t* cr);
   void PaintActiveTabBackground(GtkWidget* widget, cairo_t* cr);
   void PaintLoadingAnimation(GtkWidget* widget, cairo_t* cairo);
 
-  // Draws the given |tab_bg| onto |cr| using the tab shape masks along the
-  // sides for the rounded tab shape.
-  void DrawTabBackground(cairo_t* cr,
-                         GtkWidget* widget,
-                         const gfx::Image& tab_bg,
-                         int offset_x,
-                         int offset_y);
+  // Sets the tab background image as the source pattern within |cr|. |bounds|
+  // are the bounds of the source pattern which will be used.
+  // The tab background source pattern is generated based on whether the tab
+  // is active, whether the tab is in an incognito browser and on the current
+  // theme.
+  void SetTabBackgroundImageAsSource(cairo_t* cr,
+                                     GtkWidget* widget,
+                                     const gfx::Rect& bounds);
+
+  // Draws the tab background image onto |cr| using the tab shape masks along
+  // the sides for the rounded tab shape.
+  void DrawTabBackground(cairo_t* cr, GtkWidget* widget);
 
   // Draws the tab shadow using the given idr resources onto |cr|.
   void DrawTabShadow(cairo_t* cr,
                      GtkWidget* widget,
                      int left_idr,
                      int center_idr,
                      int right_idr);
 
   // Returns the number of favicon-size elements that can fit in the tab's
   // current size.
@@ skipping 108 matching lines @@
   // Color of the title text on the selected tab.
   SkColor selected_title_color_;
 
   // Color of the title text on an unselected tab.
   SkColor unselected_title_color_;
 
   DISALLOW_COPY_AND_ASSIGN(TabRendererGtk);
 };
 
 #endif  // CHROME_BROWSER_UI_GTK_TABS_TAB_RENDERER_GTK_H_