Fixes crash at ResourceDispatcherHost::BeginDownload...

chrome/browser/resource_dispatcher_host.cc

Index: chrome/browser/resource_dispatcher_host.cc
===================================================================
--- chrome/browser/resource_dispatcher_host.cc	(revision 6188)
+++ chrome/browser/resource_dispatcher_host.cc	(working copy)
@@ -1609,6 +1609,9 @@
   if (is_shutdown_)
     return;
 
+  if (!URLRequest::IsHandledURL(url))
+    return;
+
   // Check if the renderer is permitted to request the requested URL.
   //
   // TODO(mpcomplete): remove "render_process_host_id != -1"
@@ -1649,11 +1652,6 @@
                                            this);
   }
 
-  bool known_proto = URLRequest::IsHandledURL(url);
-  if (!known_proto) {
-    CHECK(false);
-  }
-
   request->set_method("GET");
   request->set_referrer(referrer.spec());
   request->set_context(request_context);