Make COLOR_CONTROL_BACKGROUND customizable from a theme extension

chrome/browser/themes/browser_theme_pack.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/themes/browser_theme_pack.h"
 
 #include <limits.h>
 #include <stddef.h>
 
 #include <limits>
@@ skipping 248 matching lines @@
   { "frame_inactive", ThemeProperties::TINT_FRAME_INACTIVE },
   { "frame_incognito", ThemeProperties::TINT_FRAME_INCOGNITO },
   { "frame_incognito_inactive",
     ThemeProperties::TINT_FRAME_INCOGNITO_INACTIVE },
   { "background_tab", ThemeProperties::TINT_BACKGROUND_TAB },
 };
 const size_t kTintTableLength = arraysize(kTintTable);
 
 // Strings used by themes to identify colors in the JSON.
 StringToIntTable kColorTable[] = {
+  { "control_background", ThemeProperties::COLOR_CONTROL_BACKGROUND },
   { "frame", ThemeProperties::COLOR_FRAME },
   { "frame_inactive", ThemeProperties::COLOR_FRAME_INACTIVE },
   { "frame_incognito", ThemeProperties::COLOR_FRAME_INCOGNITO },
   { "frame_incognito_inactive",
     ThemeProperties::COLOR_FRAME_INCOGNITO_INACTIVE },
   { "toolbar", ThemeProperties::COLOR_TOOLBAR },
   { "tab_text", ThemeProperties::COLOR_TAB_TEXT },
   { "tab_background_text", ThemeProperties::COLOR_BACKGROUND_TAB_TEXT },
   { "bookmark_text", ThemeProperties::COLOR_BOOKMARK_TEXT },
   { "ntp_background", ThemeProperties::COLOR_NTP_BACKGROUND },
@@ skipping 1258 matching lines @@
                                            false,
                                            &bitmap_data)) {
       NOTREACHED() << "Unable to encode theme image for prs_id="
                    << prs_id << " for scale_factor=" << scale_factors_[i];
       break;
     }
     image_memory_[scaled_raw_id] =
         base::RefCountedBytes::TakeVector(&bitmap_data);
   }
 }