Fix IsPrecachingAllowed() to check Sync instead of Data Saver.

chrome/chrome_browser.gypi

 # Copyright 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': {
     # All .cc, .h, .m, and .mm files under browser except for:
     # * tests and mocks.
     # * code below browser/chromeos
     # * code below browser/extensions
@@ skipping 628 matching lines @@
       'browser/performance_monitor/performance_monitor.cc',
       'browser/performance_monitor/performance_monitor.h',
       'browser/performance_monitor/process_metrics_history.cc',
       'browser/performance_monitor/process_metrics_history.h',
       'browser/platform_util.h',
       'browser/platform_util_android.cc',
       'browser/platform_util_chromeos.cc',
       'browser/platform_util_internal.h',
       'browser/platform_util_mac.mm',
       'browser/platform_util_win.cc',
+      'browser/precache/precache_manager_factory.cc',
+      'browser/precache/precache_manager_factory.h',
       'browser/pref_service_flags_storage.cc',
       'browser/pref_service_flags_storage.h',
       'browser/prefetch/prefetch.cc',
       'browser/prefetch/prefetch.h',
       'browser/prefetch/prefetch_field_trial.cc',
       'browser/prefetch/prefetch_field_trial.h',
       'browser/prerender/external_prerender_handler_android.cc',
       'browser/prerender/external_prerender_handler_android.h',
       'browser/prerender/prerender_config.cc',
       'browser/prerender/prerender_config.h',
@@ skipping 3397 matching lines @@
           'variables': {
             'proto_in_dir': 'browser/sync_file_system/drive_backend',
             'proto_out_dir': 'chrome/browser/sync_file_system/drive_backend',
           },
           'includes': [ '../build/protoc.gypi' ]
         },
       ],
     },],
   ],
 }