Use a valid /prefetch argument when launching a process.

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 3162 matching lines @@
         '../components/components.gyp:search',
         '../components/components.gyp:search_engines',
         '../components/components.gyp:search_provider_logos',
         '../components/components.gyp:security_interstitials_core',
         '../components/components.gyp:security_state',
         '../components/components.gyp:ssl_errors',
         '../components/components.gyp:suggestions',
         '../components/components.gyp:signin_core_browser',
         '../components/components.gyp:startup_metric_utils_browser',
         '../components/components.gyp:startup_metric_utils_browser_message_filter',
+        # TODO(fdoray): Remove this once the PreRead field trial has expired.
+        # crbug.com/577698
+        '../components/components.gyp:startup_metric_utils_common',
         '../components/components.gyp:sync_bookmarks',
         '../components/components.gyp:sync_driver',
         '../components/components.gyp:sync_sessions',
         '../components/components.gyp:translate_core_browser',
         '../components/components.gyp:translate_core_common',
         '../components/components.gyp:update_client',
         '../components/components.gyp:undo_component',
         '../components/components.gyp:user_prefs',
         '../components/components_strings.gyp:components_strings',
         # This depends directly on the variations target, rather than just
@@ skipping 994 matching lines @@
             '../components/components.gyp:omnibox_browser',
             '../components/components.gyp:rlz',
             '../components/components.gyp:search_engines',
             '../rlz/rlz.gyp:rlz_lib',
           ],
         },
       ],
     }],
   ],
 }