Manage IsolatedContext with reference counts

content/browser/renderer_host/render_view_host_impl.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.
 
 #include "content/browser/renderer_host/render_view_host_impl.h"
 
 #include <set>
 #include <string>
 #include <utility>
 #include <vector>
@@ skipping 534 matching lines @@
     }
 
     filesets.insert(path);
   }
 
   fileapi::IsolatedContext* isolated_context =
       fileapi::IsolatedContext::GetInstance();
   DCHECK(isolated_context);
   std::string filesystem_id = isolated_context->RegisterIsolatedFileSystem(
       filesets);
+  DCHECK(!filesystem_id.empty());
   policy->GrantReadFileSystem(renderer_id, filesystem_id);
   filtered_data.filesystem_id = UTF8ToUTF16(filesystem_id);
 
   Send(new DragMsg_TargetDragEnter(GetRoutingID(), filtered_data, client_pt,
                                    screen_pt, operations_allowed,
                                    key_modifiers));
 }
 
 void RenderViewHostImpl::DragTargetDragOver(
     const gfx::Point& client_pt,
@@ skipping 1278 matching lines @@
   // can cause navigations to be ignored in OnMsgNavigate.
   is_waiting_for_beforeunload_ack_ = false;
   is_waiting_for_unload_ack_ = false;
 }
 
 void RenderViewHostImpl::ClearPowerSaveBlockers() {
   STLDeleteValues(&power_save_blockers_);
 }
 
 }  // namespace content