Implement chrome.fileSystem.requestFileSystem().

chrome/renderer/resources/extensions/file_system_custom_bindings.js

 // 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.
 
 // Custom binding for the fileSystem API.
 
 var binding = require('binding').Binding.create('fileSystem');
 var sendRequest = require('sendRequest');
 
 var getFileBindingsForApi =
     require('fileEntryBindingUtil').getFileBindingsForApi;
 var fileBindings = getFileBindingsForApi('fileSystem');
 var bindFileEntryCallback = fileBindings.bindFileEntryCallback;
 var entryIdManager = fileBindings.entryIdManager;
+var fileSystemNatives = requireNative('file_system_natives');
 
 binding.registerCustomHook(function(bindingsAPI) {
   var apiFunctions = bindingsAPI.apiFunctions;
   var fileSystem = bindingsAPI.compiledApi;
 
   function bindFileEntryFunction(functionName) {
     apiFunctions.setUpdateArgumentsPostValidate(
         functionName, function(fileEntry, callback) {
       var fileSystemName = fileEntry.filesystem.name;
       var relativePath = $String.slice(fileEntry.fullPath, 1);
@@ skipping 47 matching lines @@
           callback,
           [savedEntry]);
       return [id, false, null];
     } else {
       // Ask the browser process for a new file entry for this id, to be passed
       // to |callback|.
       return [id, true, callback];
     }
   });
 
+  apiFunctions.setCustomCallback('requestFileSystem',
+      function(name, request, callback, response) {
+    var fileSystem = null;
+    if (response && response.file_system_id) {
+      fileSystem = fileSystemNatives.GetIsolatedFileSystem(
+          response.file_system_id, response.file_system_path);
+    }
+    sendRequest.safeCallbackApply(
+        'fileSystem.requestFileSystem',
+        request,
+        callback,
+        [fileSystem]);
+  });
+
   // TODO(benwells): Remove these deprecated versions of the functions.
   fileSystem.getWritableFileEntry = function() {
     console.log("chrome.fileSystem.getWritableFileEntry is deprecated");
     console.log("Please use chrome.fileSystem.getWritableEntry instead");
     $Function.apply(fileSystem.getWritableEntry, this, arguments);
   };
 
   fileSystem.isWritableFileEntry = function() {
     console.log("chrome.fileSystem.isWritableFileEntry is deprecated");
     console.log("Please use chrome.fileSystem.isWritableEntry instead");
     $Function.apply(fileSystem.isWritableEntry, this, arguments);
   };
 
   fileSystem.chooseFile = function() {
     console.log("chrome.fileSystem.chooseFile is deprecated");
     console.log("Please use chrome.fileSystem.chooseEntry instead");
     $Function.apply(fileSystem.chooseEntry, this, arguments);
   };
 });
 
 exports.bindFileEntryCallback = bindFileEntryCallback;
 exports.binding = binding.generate();