Send all field trials from the browser.

chrome/browser/renderer_host/chrome_render_message_filter.cc

 // 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.
 
 #include "chrome/browser/renderer_host/chrome_render_message_filter.h"
 
 #include <string>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
+#include "base/metrics/field_trial.h"
 #include "base/metrics/histogram.h"
 #include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/content_settings/cookie_settings.h"
 #include "chrome/browser/content_settings/tab_specific_content_settings.h"
 #include "chrome/browser/metrics/chrome_metrics_service_accessor.h"
 #include "chrome/browser/net/predictor.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/profiles/profile_manager.h"
 #include "chrome/common/render_messages.h"
 #include "components/web_cache/browser/web_cache_manager.h"
@@ skipping 54 matching lines @@
     IPC_MESSAGE_HANDLER_DELAY_REPLY(
         ChromeViewHostMsg_RequestFileSystemAccessSync,
         OnRequestFileSystemAccessSync)
     IPC_MESSAGE_HANDLER(ChromeViewHostMsg_RequestFileSystemAccessAsync,
                         OnRequestFileSystemAccessAsync)
     IPC_MESSAGE_HANDLER(ChromeViewHostMsg_AllowIndexedDB, OnAllowIndexedDB)
 #if defined(ENABLE_PLUGINS)
     IPC_MESSAGE_HANDLER(ChromeViewHostMsg_IsCrashReportingEnabled,
                         OnIsCrashReportingEnabled)
 #endif
+    IPC_MESSAGE_HANDLER(ChromeViewHostMsg_FieldTrialActivated,
+                        OnFieldTrialActivated)
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
 
   return handled;
 }
 
 void ChromeRenderMessageFilter::OverrideThreadForMessage(
     const IPC::Message& message, BrowserThread::ID* thread) {
   switch (message.type()) {
     case ChromeViewHostMsg_ResourceTypeStats::ID:
@@ skipping 259 matching lines @@
       base::Bind(&TabSpecificContentSettings::IndexedDBAccessed,
                  render_process_id_, render_frame_id, origin_url, name,
                  !*allowed));
 }
 
 #if defined(ENABLE_PLUGINS)
 void ChromeRenderMessageFilter::OnIsCrashReportingEnabled(bool* enabled) {
   *enabled = ChromeMetricsServiceAccessor::IsCrashReportingEnabled();
 }
 #endif
+
+void ChromeRenderMessageFilter::OnFieldTrialActivated(
+    const std::string& trial_name, const std::string& group_name) {

[Alexei Svitkine (slow), 2014/11/05 16:17:14]

Nit: If first param is on a new line, each param should be on a separate line.

+  base::FieldTrialList::FindFullName(trial_name);
+}