Allow SessionService to be disabled.

chrome/chrome_browser.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.
 
 {
   'targets': [
     {
       'target_name': 'browser',
       'type': 'static_library',
       'variables': { 'enable_wexit_time_destructors': 1, },
@@ skipping 4466 matching lines @@
           ],
           'sources/': [
             ['exclude', '^browser/themes/'],
           ],
         }],
         ['enable_automation!=1', {
           'sources/': [
             ['exclude', '^browser/automation/'],
           ],
         }],
+        ['enable_session_service!=1', {
+          'sources!': [
+            'browser/sessions/session_restore.cc',
+            'browser/sessions/session_service.cc',
+            'browser/sessions/session_service.h',
+            'browser/sessions/session_service_factory.cc',
+            'browser/sessions/session_service_factory.h',
+          ],
+        }],
         ['OS=="android"', {
           'sources': [
             'browser/sync/glue/synced_window_delegate_registry.cc',
             'browser/sync/glue/synced_window_delegate_registry.h',
           ],
           'sources!': [
             'browser/bookmarks/bookmark_context_menu_controller.cc',
             # Bookmark export/import are handled via the BookmarkColumns
             # ContentProvider.
             'browser/bookmarks/bookmark_html_writer.cc',
@@ skipping 13 matching lines @@
             # There's no Browser/BrowserList on Android.
             'browser/net/gaia/gaia_oauth_fetcher.cc',
             'browser/ui/browser.cc',
             'browser/ui/browser_init.cc',
             'browser/ui/browser_list.cc',
             'browser/ui/browser_list_stub.cc',
             'browser/ui/browser_navigator.cc',
             'browser/ui/browser_tab_restore_service_delegate.cc',
             'browser/ui/sync/browser_synced_window_delegate.cc',
 
-            # Custom implementation of session_restore for Android.
-            'browser/sessions/session_restore.cc',
-
             'browser/ui/sad_tab_helper.cc',
             'browser/ui/webui/certificate_viewer_webui.cc',
             'browser/ui/window_sizer.cc',
             'browser/ui/window_sizer.h',
             'browser/ui/webui/ntp/ntp_resource_cache.cc',
             'browser/upgrade_detector.cc',
             'browser/upgrade_detector.h',
             'browser/upgrade_detector_impl.cc',
             'browser/upgrade_detector_impl.h',
           ],
@@ skipping 760 matching lines @@
          'variables': {
           'proto_in_dir': '../third_party/cros_system_api/dbus/',
           'proto_out_dir': 'chrome/browser/chromeos/dbus',
          },
          'includes': ['../build/protoc.gypi'],
         }],
       ],
     },
   ],
 }