Fix crash bug when attempting to download a url with unsupported scheme, e.g....

chrome/browser/renderer_host/resource_dispatcher_host.cc

 // Copyright (c) 2009 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // See http://dev.chromium.org/developers/design-documents/multi-process-resource-loading
 
 #include "chrome/browser/renderer_host/resource_dispatcher_host.h"
 
 #include <vector>
 
@@ skipping 711 matching lines @@
     handler = new SafeBrowsingResourceHandler(handler,
                                               child_id,
                                               route_id,
                                               url,
                                               ResourceType::MAIN_FRAME,
                                               safe_browsing_,
                                               this,
                                               receiver_);
   }
 
-  bool known_proto = URLRequest::IsHandledURL(url);
-  if (!known_proto) {
-    CHECK(false);
+  if (!URLRequest::IsHandledURL(url)) {
+    LOG(INFO) << "Download request for unsupported protocol: " <<
+        url.possibly_invalid_spec();
+    return;
   }
 
   request->set_method("GET");
   request->set_referrer(referrer.spec());
   request->set_context(request_context);
   request->set_load_flags(request->load_flags() |
       net::LOAD_IS_DOWNLOAD);
 
   ResourceDispatcherHostRequestInfo* extra_info =
       new ResourceDispatcherHostRequestInfo(handler,
@@ skipping 1030 matching lines @@
     case ViewHostMsg_UploadProgress_ACK::ID:
     case ViewHostMsg_SyncLoad::ID:
       return true;
 
     default:
       break;
   }
 
   return false;
 }