Add prerender to ChromeOS.

chrome/browser/prerender/prerender_field_trial.cc

 // Copyright (c) 2011 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/prerender/prerender_field_trial.h"
 
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/metrics/field_trial.h"
 #include "base/metrics/histogram.h"
@@ skipping 29 matching lines @@
     } else if (switch_value == switches::kPrerenderSwitchValuePrefetchOnly) {
       prerender_option = PRERENDER_OPTION_PREFETCH_ONLY;
     } else {
       prerender_option = PRERENDER_OPTION_DISABLED;
       LOG(ERROR) << "Invalid --prerender option received on command line: "
                  << switch_value;
       LOG(ERROR) << "Disabling prerendering!";
     }
   }
 
-#if defined(OS_CHROMEOS)
-  // Prerender is not enabled on CrOS by default..
-  // http://crosbug.com/12483
-  if (prerender_option == PRERENDER_OPTION_AUTO)
-    prerender_option = PRERENDER_OPTION_DISABLED;
-#endif
-
   switch (prerender_option) {
     case PRERENDER_OPTION_AUTO: {
       const base::FieldTrial::Probability kPrefetchDivisor = 1000;
       const base::FieldTrial::Probability kYesPrefetchProbability = 0;
       const base::FieldTrial::Probability kPrerenderExp1Probability = 400;
       const base::FieldTrial::Probability kPrerenderControl1Probability = 100;
       const base::FieldTrial::Probability kPrerenderExp2Probability = 400;
       const base::FieldTrial::Probability kPrerenderControl2Probability = 100;
 
       scoped_refptr<base::FieldTrial> trial(
@@ skipping 53 matching lines @@
     default:
       NOTREACHED();
   }
 
   UMA_HISTOGRAM_ENUMERATION("Prerender.Sessions",
                             PrerenderManager::GetMode(),
                             PrerenderManager::PRERENDER_MODE_MAX);
 }
 
 }  // namespace prerender