Improve panel related tests to make them more reliable

chrome/chrome_tests.gypi

 # Copyright 2013 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.
 {
   'variables' : {
     'pyautolib_sources': [
       'app/chrome_command_ids.h',
       'app/chrome_dll_resource.h',
       'common/automation_constants.h',
       'common/pref_names.cc',
@@ skipping 206 matching lines @@
         'browser/ui/panels/panel_browsertest.cc',
         'browser/ui/panels/panel_drag_browsertest.cc',
         'browser/ui/panels/panel_resize_browsertest.cc',
         'browser/ui/panels/stacked_panel_browsertest.cc',
         'browser/ui/panels/test_panel_active_state_observer.cc',
         'browser/ui/panels/test_panel_active_state_observer.h',
         'browser/ui/panels/test_panel_mouse_watcher.cc',
         'browser/ui/panels/test_panel_mouse_watcher.h',
         'browser/ui/panels/test_panel_notification_observer.cc',
         'browser/ui/panels/test_panel_notification_observer.h',
-        'browser/ui/panels/test_panel_collection_squeeze_observer.cc',
-        'browser/ui/panels/test_panel_collection_squeeze_observer.h',
         'browser/ui/search/instant_browsertest.cc',
         'browser/ui/search/instant_extended_browsertest.cc',
         'browser/ui/search/instant_extended_manual_browsertest.cc',
         'browser/ui/search/instant_test_utils.h',
         'browser/ui/search/instant_test_utils.cc',
         'browser/ui/startup/startup_browser_creator_interactive_uitest.cc',
         'browser/ui/views/ash/tab_scrubber_browsertest.cc',
         'browser/ui/views/bookmarks/bookmark_bar_view_test.cc',
         'browser/ui/views/button_dropdown_test.cc',
         'browser/ui/views/constrained_window_views_browsertest.cc',
@@ skipping 2990 matching lines @@
               # more details.
               'DebugInformationFormat': '3',
               'ProgramDataBaseFileName': '<(PRODUCT_DIR)/browser_tests.exe.pdb',
             },
           },
         },
       ],
     }],
   ],  # 'conditions'
 }