Add navigation controls to DevTools screencast view

Source/devtools/devtools.gyp

 #
 # Copyright (C) 2013 Google Inc. All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #         * Redistributions of source code must retain the above copyright
 # notice, this list of conditions and the following disclaimer.
 #         * Redistributions in binary form must reproduce the above
@@ skipping 374 matching lines @@
             'front_end/Images/glossyHeader.png',
             'front_end/Images/glossyHeaderPressed.png',
             'front_end/Images/glossyHeaderSelected.png',
             'front_end/Images/glossyHeaderSelectedPressed.png',
             'front_end/Images/graphLabelCalloutLeft.png',
             'front_end/Images/graphLabelCalloutRight.png',
             'front_end/Images/indexedDB.png',
             'front_end/Images/indexedDBObjectStore.png',
             'front_end/Images/indexedDBIndex.png',
             'front_end/Images/localStorage.png',
+            'front_end/Images/navigationControls.png',
+            'front_end/Images/navigationControls_2x.png',
             'front_end/Images/paneAddButtons.png',
             'front_end/Images/paneElementStateButtons.png',
             'front_end/Images/paneFilterButtons.png',
             'front_end/Images/paneRefreshButtons.png',
             'front_end/Images/paneSettingsButtons.png',
             'front_end/Images/popoverArrows.png',
             'front_end/Images/popoverBackground.png',
             'front_end/Images/profileGroupIcon.png',
             'front_end/Images/profileIcon.png',
             'front_end/Images/profileSmallIcon.png',
@@ skipping 519 matching lines @@
                         'destination': '<(PRODUCT_DIR)/resources/inspector',
                         'files': [
                             '<@(devtools_standalone_files)',
                         ],
                     }],
                 },
             ],
         }],
     ], # conditions
 }