Fix bug when drawing background tabs in incognito windows with custom themes.

chrome/browser/ui/views/tabs/tab_strip.cc

 // 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.
 
 #include "chrome/browser/ui/views/tabs/tab_strip.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 #include <iterator>
@@ skipping 1378 matching lines @@
 
   if (GetWidget()->ShouldWindowContentsBeTransparent()) {
     const int kBackgroundIdGlass = IDR_THEME_TAB_BACKGROUND_V;
     *custom_image = tp->HasCustomImage(kBackgroundIdGlass);
     return kBackgroundIdGlass;
   }
 
   // If a custom theme does not provide a replacement tab background, but does
   // provide a replacement frame image, HasCustomImage() on the tab background
   // ID will return false, but the theme provider will make a custom image from
-  // the frame image.
+  // the frame image.  Furthermore, since the theme provider will create the
+  // incognito frame image from the normal frame image, in incognito mode we
+  // need to look for a custom incognito _or_ regular frame image.
   const bool incognito = controller()->IsIncognito();
   const int id = incognito ?
       IDR_THEME_TAB_BACKGROUND_INCOGNITO : IDR_THEME_TAB_BACKGROUND;
   const int frame_id = incognito ? IDR_THEME_FRAME_INCOGNITO : IDR_THEME_FRAME;
-  *custom_image = tp->HasCustomImage(id) || tp->HasCustomImage(frame_id);
+  *custom_image = tp->HasCustomImage(id) || tp->HasCustomImage(frame_id) ||
+      (incognito && tp->HasCustomImage(IDR_THEME_FRAME));
   return id;
 }
 
 void TabStrip::UpdateTabAccessibilityState(const Tab* tab,
                                            ui::AXViewState* state) {
   state->count = tab_count();
   state->index = GetModelIndexOfTab(tab);
 }
 
 void TabStrip::MouseMovedOutOfHost() {
@@ skipping 1453 matching lines @@
           ConvertPointToViewAndGetEventHandler(this, newtab_button_, point);
       if (view)
         return view;
     }
     Tab* tab = FindTabForEvent(point);
     if (tab)
       return ConvertPointToViewAndGetEventHandler(this, tab, point);
   }
   return this;
 }