Add PanelOverflowStrip to handle panel overflow.

chrome/chrome_browser.gypi

 # Copyright (c) 2011 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.
 
 {
   'targets': [
     {
       'target_name': 'browser',
       'type': 'static_library',
       'variables': { 'enable_wexit_time_destructors': 1, },
@@ skipping 3185 matching lines @@
         'browser/ui/panels/panel_browser_window_cocoa.mm',
         'browser/ui/panels/panel_browser_window_gtk.cc',
         'browser/ui/panels/panel_browser_window_gtk.h',
         'browser/ui/panels/panel_manager.cc',
         'browser/ui/panels/panel_manager.h',
         'browser/ui/panels/panel_mouse_watcher.cc',
         'browser/ui/panels/panel_mouse_watcher.h',
         'browser/ui/panels/panel_mouse_watcher_observer.h',
         'browser/ui/panels/panel_mouse_watcher_timer.cc',
         'browser/ui/panels/panel_mouse_watcher_win.cc',
+        'browser/ui/panels/panel_overflow_strip.cc',
+        'browser/ui/panels/panel_overflow_strip.h',
         'browser/ui/panels/panel_settings_menu_model.cc',
         'browser/ui/panels/panel_settings_menu_model.h',
         'browser/ui/panels/panel_strip.cc',
         'browser/ui/panels/panel_strip.h',
         'browser/ui/panels/panel_titlebar_view_cocoa.h',
         'browser/ui/panels/panel_titlebar_view_cocoa.mm',
         'browser/ui/panels/panel_window_controller_cocoa.h',
         'browser/ui/panels/panel_window_controller_cocoa.mm',
         'browser/ui/profile_error_dialog.cc',
         'browser/ui/profile_error_dialog.h',
@@ skipping 2017 matching lines @@
       'type': 'static_library',
       'sources': [ 'browser/history/in_memory_url_index_cache.proto' ],
       'variables': {
         'proto_in_dir': 'browser/history',
         'proto_out_dir': 'chrome/browser/history',
       },
       'includes': [ '../build/protoc.gypi' ]
     },
   ],
 }