Don't process messages sent to dead routing ids.

content/browser/renderer_host/render_widget_host_impl.cc

Index: content/browser/renderer_host/render_widget_host_impl.cc
diff --git a/content/browser/renderer_host/render_widget_host_impl.cc b/content/browser/renderer_host/render_widget_host_impl.cc
index 87b8550a13a87dd368dfe1760ef055784473cd91..17812f352abae799c30f5738c4c40e772b3dd6f7 100644
--- a/content/browser/renderer_host/render_widget_host_impl.cc
+++ b/content/browser/renderer_host/render_widget_host_impl.cc
@@ -437,6 +437,10 @@ bool RenderWidgetHostImpl::IsLoading() const {
 }
 
 bool RenderWidgetHostImpl::OnMessageReceived(const IPC::Message &msg) {
+  // Only process messages if the RenderWidget is alive.
+  if (!renderer_initialized())
+    return false;
+
   if (owner_delegate_ && owner_delegate_->OnMessageReceived(msg))
     return true;