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

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

Index: chrome/browser/ui/views/tabs/tab_strip.cc
diff --git a/chrome/browser/ui/views/tabs/tab_strip.cc b/chrome/browser/ui/views/tabs/tab_strip.cc
index 845992736580ac758a36b5adcd9f589d883f409c..d60676d95acbb7b4644d83357e082822c5eec77d 100644
--- a/chrome/browser/ui/views/tabs/tab_strip.cc
+++ b/chrome/browser/ui/views/tabs/tab_strip.cc
@@ -1396,12 +1396,15 @@ int TabStrip::GetBackgroundResourceId(bool* custom_image) const {
   // 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;
 }