Cache the current WebPreferences on RenderViewHostImpl.

content/browser/renderer_host/render_view_host_impl.cc

Index: content/browser/renderer_host/render_view_host_impl.cc
diff --git a/content/browser/renderer_host/render_view_host_impl.cc b/content/browser/renderer_host/render_view_host_impl.cc
index a5b1d60bf3e68d657fe029a21db820d4e4bfbfdd..3f1a0e66eb7ac672fb5b2c27865ff148cf7efc33 100644
--- a/content/browser/renderer_host/render_view_host_impl.cc
+++ b/content/browser/renderer_host/render_view_host_impl.cc
@@ -289,7 +289,7 @@ bool RenderViewHostImpl::CreateRenderView(
   ViewMsg_New_Params params;
   params.renderer_preferences =
       delegate_->GetRendererPrefs(GetProcess()->GetBrowserContext());
-  params.web_preferences = delegate_->GetWebkitPrefs();
+  params.web_preferences = GetWebkitPreferences();
   params.view_id = GetRoutingID();
   params.main_frame_routing_id = main_frame_routing_id_;
   params.surface_id = surface_id();
@@ -329,7 +329,7 @@ void RenderViewHostImpl::SyncRendererPrefs() {
                                         GetProcess()->GetBrowserContext())));
 }
 
-WebPreferences RenderViewHostImpl::GetWebkitPrefs(const GURL& url) {
+WebPreferences RenderViewHostImpl::ComputeWebkitPrefs(const GURL& url) {
   TRACE_EVENT0("browser", "RenderViewHostImpl::GetWebkitPrefs");
   WebPreferences prefs;
 
@@ -1420,7 +1420,10 @@ void RenderViewHostImpl::ExitFullscreen() {
 }
 
 WebPreferences RenderViewHostImpl::GetWebkitPreferences() {
-  return delegate_->GetWebkitPrefs();
+  if (!web_preferences_.get()) {
+    OnWebkitPreferencesChanged();
+  }
+  return *web_preferences_;
 }
 
 void RenderViewHostImpl::DisownOpener() {
@@ -1431,9 +1434,14 @@ void RenderViewHostImpl::DisownOpener() {
 }
 
 void RenderViewHostImpl::UpdateWebkitPreferences(const WebPreferences& prefs) {
+  web_preferences_.reset(new WebPreferences(prefs));
   Send(new ViewMsg_UpdateWebPreferences(GetRoutingID(), prefs));
 }
 
+void RenderViewHostImpl::OnWebkitPreferencesChanged() {
+  UpdateWebkitPreferences(delegate_->ComputeWebkitPrefs());
+}
+
 void RenderViewHostImpl::GetAudioOutputControllers(
     const GetAudioOutputControllersCallback& callback) const {
   AudioRendererHost* audio_host =