Don't build sync_integration_tests by default for official builds.

BUILD.gn

 # Copyright (c) 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.
 
 # This is the root build file for GN. GN will start processing by loading this
 # file, and recursively load all dependencies until all dependencies are either
 # resolved or known not to exist (which will cause the build to fail). So if
 # you add a new build file, there must be some path of dependencies from this
 # file to your new one or GN won't know about it.
 
@@ skipping 740 matching lines @@
     }
   }
 
   group("chrome_official_builder") {
     testonly = true
 
     deps = [
       ":chrome_official_builder_no_unittests",
       "//base:base_unittests",
       "//chrome/test:browser_tests",
-      "//chrome/test:sync_integration_tests",
       "//ipc:ipc_tests",
       "//media:media_unittests",
       "//media/midi:midi_unittests",
       "//net:net_unittests",
       "//printing:printing_unittests",
       "//sql:sql_unittests",
       "//ui/base:ui_base_unittests",
       "//ui/gfx:gfx_unittests",
       "//ui/touch_selection:ui_touch_selection_unittests",
       "//ui/views:views_unittests",
@@ skipping 296 matching lines @@
   assert(target_name != "")  # Mark as used.
   sources = invoker.actual_sources
   assert(
       sources == invoker.actual_sources,
       "Do not use a platform name in your output directory (found \"$root_build_dir\"). http://crbug.com/548283")
 }
 
 assert_valid_out_dir("_unused") {
   actual_sources = [ "$root_build_dir/foo" ]
 }