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

content/renderer/render_view_impl.cc

Index: content/renderer/render_view_impl.cc
diff --git a/content/renderer/render_view_impl.cc b/content/renderer/render_view_impl.cc
index 203ee4bf33b1a3fbbc2b38b4f240c3c975d79cbc..442c2da01c1a20aa76d2c88c21dfc3732466bc67 100644
--- a/content/renderer/render_view_impl.cc
+++ b/content/renderer/render_view_impl.cc
@@ -1068,6 +1068,8 @@ void RenderView::ApplyWebPreferences(const WebPreferences& prefs,
   settings->setV8CacheOptions(
       static_cast<WebSettings::V8CacheOptions>(prefs.v8_cache_options));
 
+  settings->setV8ScriptStreamingEnabled(prefs.v8_script_streaming_enabled);
+
 #if defined(OS_ANDROID)
   settings->setAllowCustomScrollbarInMainFrame(false);
   settings->setTextAutosizingEnabled(prefs.text_autosizing_enabled);