Fix media galleries crash when the window is closed with config dialog open.

chrome/browser/extensions/api/media_galleries/media_galleries_api.cc

 // Copyright (c) 2012 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.
 
 // Implements the Chrome Extensions Media Galleries API.
 
 #include "chrome/browser/extensions/api/media_galleries/media_galleries_api.h"
 
 #include <set>
 #include <string>
@@ skipping 103 matching lines @@
 }
 
 void MediaGalleriesGetMediaFileSystemsFunction::GetAndReturnGalleries() {
   MediaFileSystemRegistry::GetInstance()->GetMediaFileSystemsForExtension(
       render_view_host(), GetExtension(), base::Bind(
           &MediaGalleriesGetMediaFileSystemsFunction::ReturnGalleries, this));
 }
 
 void MediaGalleriesGetMediaFileSystemsFunction::ReturnGalleries(
     const std::vector<MediaFileSystemInfo>& filesystems) {
-  const int child_id = render_view_host()->GetProcess()->GetID();
+  content::RenderViewHost* rvh = render_view_host();
+  if (!rvh) {
+    SendResponse(false);
+    return;
+  }
+  const int child_id = rvh->GetProcess()->GetID();
   std::set<std::string> file_system_names;
   base::ListValue* list = new base::ListValue();
   for (size_t i = 0; i < filesystems.size(); i++) {
     scoped_ptr<base::DictionaryValue> file_system_dict_value(
         new base::DictionaryValue());
 
     // Send the file system id so the renderer can create a valid FileSystem
     // object.
     file_system_dict_value->SetWithoutPathExpansion(
         "fsid", Value::CreateStringValue(filesystems[i].fsid));
@@ skipping 54 matching lines @@
 bool MediaGalleriesAssembleMediaFileFunction::RunImpl() {
   if (!ApiIsAccessible(&error_))
     return false;
 
   // TODO(vandebo) Update the metadata and return the new file.
   SetResult(Value::CreateNullValue());
   return true;
 }
 
 }  // namespace extensions