Linux/CrOS smooth scrolling support - behind a flag.

webkit/glue/webkit_glue.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.
 
 {
   'variables': {
     'conditions': [
       ['inside_chromium_build==0', {
         'webkit_src_dir': '../../../../..',
       },{
@@ skipping 503 matching lines @@
           'dependencies': [
             '<(DEPTH)/webkit/support/setup_third_party.gyp:third_party_headers',
           ],
         }],
         ['p2p_apis==1', {
           'sources': [
             '../plugins/ppapi/ppb_transport_impl.cc',
             '../plugins/ppapi/ppb_transport_impl.h',
           ],
         }],
+        ['OS=="linux" and enable_smooth_scrolling==1', {
+          'defines': [
+            'ENABLE_SMOOTH_SCROLLING',
+          ],
+        }],
       ],
     },
   ],
   'conditions': [
     ['use_third_party_translations==1', {
       'targets': [
         {
           'target_name': 'inspector_strings',
           'type': 'none',
           'variables': {
             'grit_out_dir': '<(PRODUCT_DIR)/resources/inspector/l10n',
           },
           'actions': [
             {
               'action_name': 'inspector_strings',
               'variables': {
                 'grit_grd_file': 'inspector_strings.grd',
               },
               'includes': [ '../../build/grit_action.gypi' ],
             },
           ],
           'includes': [ '../../build/grit_target.gypi' ],
         },
       ],
     }],
   ],
 }