DevTools: do not abuse inspector controller for the front-end side plumbing.

Source/modules/filesystem/DevToolsHostFileSystem.cpp

 // Copyright 2014 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 "config.h"
 #include "modules/filesystem/DevToolsHostFileSystem.h"
 
 #include "core/dom/Document.h"
 #include "core/frame/LocalFrame.h"
 #include "core/inspector/DevToolsHost.h"
 #include "core/page/Page.h"
 #include "modules/filesystem/DOMFileSystem.h"
 #include "platform/JSONValues.h"
 
 namespace blink {
 
 DOMFileSystem* DevToolsHostFileSystem::isolatedFileSystem(DevToolsHost& host, const String& fileSystemName, const String& rootURL)
 {
-    ExecutionContext* context = host.frontendPage()->deprecatedLocalMainFrame()->document();
+    ExecutionContext* context = host.frontendFrame()->document();
     return DOMFileSystem::create(context, fileSystemName, FileSystemTypeIsolated, KURL(ParsedURLString, rootURL));
 }
 
 void DevToolsHostFileSystem::upgradeDraggedFileSystemPermissions(DevToolsHost& host, DOMFileSystem* domFileSystem)
 {
     RefPtr<JSONObject> message = JSONObject::create();
     message->setNumber("id", 0);
     message->setString("method", "upgradeDraggedFileSystemPermissions");
     RefPtr<JSONArray> params = JSONArray::create();
     message->setArray("params", params);
     params->pushString(domFileSystem->rootURL().string());
     host.sendMessageToEmbedder(message->toJSONString());
 }
 
 DevToolsHostFileSystem::DevToolsHostFileSystem() { }
 
 DevToolsHostFileSystem::~DevToolsHostFileSystem() { }
 
 
 } // namespace blink