Remove all exclude rules that filename_rules.gypi already handles.

webkit/common/webkit_common.gyp

 # 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': {
     'enable_wexit_time_destructors': 1,
     'chromium_code': 1
   },
   'targets': [
@@ skipping 66 matching lines @@
         ['use_aura==1 and use_x11==1', {
           'link_settings': {
             'libraries': [ '-lXcursor', ],
           },
         }],
         ['use_ozone==0', {
           'sources!': [
             'cursors/webcursor_null.cc',
           ],
         }],
-        ['OS!="mac"', {
-          'sources/': [['exclude', '_mac\\.(cc|mm)$']],
-        }, {  # else: OS=="mac"
+        ['OS=="mac"', {
           'link_settings': {
             'libraries': [
               '$(SDKROOT)/System/Library/Frameworks/QuartzCore.framework',
             ],
           },
         }],
-        ['OS!="win"', {
-          'sources/': [['exclude', '_win\\.cc$']],
-        }, {  # else: OS=="win"
+        ['OS=="win"', {
           # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
           'msvs_disabled_warnings': [ 4800, 4267 ],
-          'sources/': [['exclude', '_posix\\.cc$']],
         }],
       ],
     },
   ],
 }