Refactor Pickle Read methods to use higher performance PickleIterator.

content/browser/renderer_host/render_view_host.cc

Index: content/browser/renderer_host/render_view_host.cc
diff --git a/content/browser/renderer_host/render_view_host.cc b/content/browser/renderer_host/render_view_host.cc
index e193dc2e71f586ccbb9a6cb3ec494e4606e7833a..ec0145fbbd067711f77344ae77f815d212db8231 100644
--- a/content/browser/renderer_host/render_view_host.cc
+++ b/content/browser/renderer_host/render_view_host.cc
@@ -924,7 +924,7 @@ void RenderViewHost::OnMsgRenderViewGone(int status, int exit_code) {
 void RenderViewHost::OnMsgNavigate(const IPC::Message& msg) {
   // Read the parameters out of the IPC message directly to avoid making another
   // copy when we filter the URLs.
-  void* iter = NULL;
+  PickleReader iter(msg);
   ViewHostMsg_FrameNavigate_Params validated_params;
   if (!IPC::ParamTraits<ViewHostMsg_FrameNavigate_Params>::
       Read(&msg, &iter, &validated_params))