[Cleanup] Remove the obsolete Prerender field trial.

chrome/browser/android/chrome_startup_flags.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 <jni.h>
 
 #include "chrome/browser/android/chrome_startup_flags.h"
 
 #include "base/android/jni_android.h"
 #include "base/android/jni_string.h"
@@ skipping 17 matching lines @@
 void SetCommandLineSwitchASCII(const std::string& switch_string,
                                const std::string& value) {
   base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
   if (!command_line->HasSwitch(switch_string))
     command_line->AppendSwitchASCII(switch_string, value);
 }
 
 }  // namespace
 
 void SetChromeSpecificCommandLineFlags() {
-  // Enable prerender with holdback.
-  SetCommandLineSwitchASCII(switches::kPrerenderMode,
-                            switches::kPrerenderModeSwitchValueAuto);
-
   // Enable prerender for the omnibox.
   SetCommandLineSwitchASCII(switches::kPrerenderFromOmnibox,
                             switches::kPrerenderFromOmniboxSwitchValueEnabled);
 
   // Disable syncing favicons on low end devices.
   if (base::SysInfo::IsLowEndDevice())
     SetCommandLineSwitchASCII(switches::kDisableSyncTypes, "Favicon Images");
 
   // Enable DOM Distiller backend.
   SetCommandLineSwitch(switches::kEnableDomDistiller);
 }