Add a command line option and a Finch experiment for script streaming.

content/browser/renderer_host/render_view_host_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/renderer_host/render_view_host_impl.h"
 
 #include <set>
 #include <string>
 #include <utility>
 #include <vector>
 
 #include "base/callback.h"
 #include "base/command_line.h"
 #include "base/debug/trace_event.h"
 #include "base/i18n/rtl.h"
 #include "base/json/json_reader.h"
 #include "base/message_loop/message_loop.h"
+#include "base/metrics/field_trial.h"
 #include "base/metrics/histogram.h"
 #include "base/stl_util.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/sys_info.h"
 #include "base/time/time.h"
 #include "base/values.h"
 #include "cc/base/switches.h"
 #include "content/browser/child_process_security_policy_impl.h"
 #include "content/browser/dom_storage/session_storage_namespace_impl.h"
@@ skipping 441 matching lines @@
         command_line.GetSwitchValueASCII(switches::kV8CacheOptions);
     if (v8_cache_options == "parse") {
       prefs.v8_cache_options = V8_CACHE_OPTIONS_PARSE;
     } else if (v8_cache_options == "code") {
       prefs.v8_cache_options = V8_CACHE_OPTIONS_CODE;
     } else {
       prefs.v8_cache_options = V8_CACHE_OPTIONS_OFF;
     }
   }
 
+  prefs.v8_script_streaming_enabled =
+      command_line.HasSwitch(switches::kEnableV8ScriptStreaming) ||
+      base::FieldTrialList::FindFullName("V8ScriptStreaming") == "Enabled";
+
   GetContentClient()->browser()->OverrideWebkitPrefs(this, url, &prefs);
   return prefs;
 }
 
 void RenderViewHostImpl::Navigate(const FrameMsg_Navigate_Params& params) {
   TRACE_EVENT0("renderer_host,navigation", "RenderViewHostImpl::Navigate");
   delegate_->GetFrameTree()->GetMainFrame()->Navigate(params);
 }
 
 void RenderViewHostImpl::NavigateToURL(const GURL& url) {
@@ skipping 1022 matching lines @@
   FrameTree* frame_tree = delegate_->GetFrameTree();
 
   frame_tree->ResetForMainFrameSwap();
 }
 
 void RenderViewHostImpl::SelectWordAroundCaret() {
   Send(new ViewMsg_SelectWordAroundCaret(GetRoutingID()));
 }
 
 }  // namespace content