Use a different algorithm with the low entropy source for field trials.

chrome/chrome_common.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': 'common',
       'type': 'static_library',
       'variables': {
@@ skipping 31 matching lines @@
         '<(DEPTH)/content/content.gyp:content_common',
         '<(DEPTH)/ipc/ipc.gyp:ipc',
         '<(DEPTH)/net/net.gyp:net',
         '<(DEPTH)/printing/printing.gyp:printing',
         '<(DEPTH)/skia/skia.gyp:skia',
         '<(DEPTH)/third_party/adobe/flash/flash_player.gyp:flapper_version_h',
         '<(DEPTH)/third_party/bzip2/bzip2.gyp:bzip2',
         '<(DEPTH)/third_party/icu/icu.gyp:icui18n',
         '<(DEPTH)/third_party/icu/icu.gyp:icuuc',
         '<(DEPTH)/third_party/libxml/libxml.gyp:libxml',
+        '<(DEPTH)/third_party/mt19937ar/mt19937ar.gyp:mt19937ar',
         '<(DEPTH)/third_party/sqlite/sqlite.gyp:sqlite',
         '<(DEPTH)/third_party/zlib/zlib.gyp:zlib',
         '<(DEPTH)/ui/ui.gyp:ui_resources',
         '<(DEPTH)/webkit/support/webkit_support.gyp:glue',
       ],
       'sources': [
         'common/all_messages.h',
         'common/attrition_experiments.h',
         'common/auto_start_linux.cc',
         'common/auto_start_linux.h',
@@ skipping 162 matching lines @@
         'common/mac/app_mode_common.h',
         'common/mac/app_mode_common.mm',
         'common/mac/cfbundle_blocker.h',
         'common/mac/cfbundle_blocker.mm',
         'common/mac/launchd.h',
         'common/mac/launchd.mm',
         'common/mac/objc_method_swizzle.h',
         'common/mac/objc_method_swizzle.mm',
         'common/mac/objc_zombie.h',
         'common/mac/objc_zombie.mm',
+        'common/metrics/entropy_provider.cc',
+        'common/metrics/entropy_provider.h',
         'common/metrics/metrics_log_base.cc',
         'common/metrics/metrics_log_base.h',
         'common/metrics/metrics_log_manager.cc',
         'common/metrics/metrics_log_manager.h',
         'common/metrics/metrics_service_base.cc',
         'common/metrics/metrics_service_base.h',
         'common/metrics/variations/variations_util.cc',
         'common/metrics/variations/variations_util.h',
         'common/multi_process_lock.h',
         'common/multi_process_lock_linux.cc',
@@ skipping 305 matching lines @@
         'common/metrics/proto/user_action_event.proto',
       ],
       'variables': {
         'proto_in_dir': 'common/metrics/proto',
         'proto_out_dir': 'chrome/common/metrics/proto',
       },
       'includes': [ '../build/protoc.gypi' ],
     },
   ],
 }