Remove unused paintScrollbarThumb impl.

content/content_shell.gypi

 # 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.
 
 {
   'variables': {
     'content_shell_product_name': 'Content Shell',
     # The "19" is so that sites that sniff for version think that this is
     # something reasonably current; the "77.34.5" is a hint that this isn't a
     # standard Chrome.
@@ skipping 213 matching lines @@
         'shell/renderer/test_runner/mock_web_media_stream_center.cc',
         'shell/renderer/test_runner/mock_web_media_stream_center.h',
         'shell/renderer/test_runner/mock_web_midi_accessor.cc',
         'shell/renderer/test_runner/mock_web_midi_accessor.h',
         'shell/renderer/test_runner/mock_web_push_client.cc',
         'shell/renderer/test_runner/mock_web_push_client.h',
         'shell/renderer/test_runner/mock_web_speech_recognizer.cc',
         'shell/renderer/test_runner/mock_web_speech_recognizer.h',
         'shell/renderer/test_runner/mock_web_theme_engine.cc',
         'shell/renderer/test_runner/mock_web_theme_engine.h',
-        'shell/renderer/test_runner/mock_web_theme_engine_mac.h',
-        'shell/renderer/test_runner/mock_web_theme_engine_mac.mm',
         'shell/renderer/test_runner/mock_web_user_media_client.cc',
         'shell/renderer/test_runner/mock_web_user_media_client.h',
         'shell/renderer/test_runner/mock_webrtc_data_channel_handler.cc',
         'shell/renderer/test_runner/mock_webrtc_data_channel_handler.h',
         'shell/renderer/test_runner/mock_webrtc_dtmf_sender_handler.cc',
         'shell/renderer/test_runner/mock_webrtc_dtmf_sender_handler.h',
         'shell/renderer/test_runner/mock_webrtc_peer_connection_handler.cc',
         'shell/renderer/test_runner/mock_webrtc_peer_connection_handler.h',
         'shell/renderer/test_runner/notification_presenter.cc',
         'shell/renderer/test_runner/notification_presenter.h',
@@ skipping 885 matching lines @@
                 '--input_symbol', '<(PRODUCT_DIR)/content_shell.exe.pdb',
                 '--destination_dir', '<(dest_dir)',
               ],
             },
           ],
         },
       ],
     }],  # OS=="win" and fastbuild==0 and target_arch=="ia32"
   ]
 }