Enable the threaded HTML parser by default

content/browser/web_contents/web_contents_impl.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 "content/browser/web_contents/web_contents_impl.h"
 
 #include <utility>
 
 #include "base/command_line.h"
 #include "base/metrics/histogram.h"
@@ skipping 518 matching lines @@
       command_line.HasSwitch(switches::kEnableExperimentalWebKitFeatures);
   prefs.css_shaders_enabled =
       command_line.HasSwitch(switches::kEnableCssShaders);
   prefs.css_variables_enabled =
       command_line.HasSwitch(switches::kEnableExperimentalWebKitFeatures);
   prefs.css_grid_layout_enabled =
       command_line.HasSwitch(switches::kEnableExperimentalWebKitFeatures);
   prefs.record_rendering_stats =
       command_line.HasSwitch(switches::kEnableGpuBenchmarking);
   prefs.threaded_html_parser =
-      command_line.HasSwitch(switches::kEnableThreadedHTMLParser);
+      !command_line.HasSwitch(switches::kDisableThreadedHTMLParser);
 
   bool touch_device_present = false;
   touch_device_present = ui::IsTouchDevicePresent();
   const std::string touch_enabled_switch =
       command_line.HasSwitch(switches::kTouchEvents) ?
       command_line.GetSwitchValueASCII(switches::kTouchEvents) :
       switches::kTouchEventsAuto;
 
   if (touch_enabled_switch.empty() ||
       touch_enabled_switch == switches::kTouchEventsEnabled) {
@@ skipping 2986 matching lines @@
 
 BrowserPluginGuest* WebContentsImpl::GetBrowserPluginGuest() const {
   return browser_plugin_guest_.get();
 }
 
 BrowserPluginEmbedder* WebContentsImpl::GetBrowserPluginEmbedder() const {
   return browser_plugin_embedder_.get();
 }
 
 }  // namespace content