Change chrome.filesystem to handle the Chrome OS Drive file entries directly.

chrome/browser/extensions/api/file_system/file_system_api.h

 // 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.
 
 #ifndef CHROME_BROWSER_EXTENSIONS_API_FILE_SYSTEM_FILE_SYSTEM_API_H_
 #define CHROME_BROWSER_EXTENSIONS_API_FILE_SYSTEM_FILE_SYSTEM_API_H_
 
 #include "chrome/browser/extensions/extension_function.h"
 #include "chrome/common/extensions/api/file_system.h"
 #include "ui/shell_dialogs/select_file_dialog.h"
@@ skipping 55 matching lines @@
   virtual ~FileSystemIsWritableEntryFunction() {}
   virtual bool RunImpl() OVERRIDE;
 };
 
 class FileSystemChooseEntryFunction : public FileSystemEntryFunction {
  public:
   // Allow picker UI to be skipped in testing.
   static void SkipPickerAndAlwaysSelectPathForTest(base::FilePath* path);
   static void SkipPickerAndAlwaysCancelForTest();
   static void StopSkippingPickerForTest();
+  static void RegisterTempExternalFileSystemForTest(const std::string& name,

[benwells, 2013/03/25 10:08:13]

Could you add a comment here explaining when this needs to be done?

[kinaba, 2013/03/25 12:07:51]

Done.

+                                                    const base::FilePath& path);
 
   DECLARE_EXTENSION_FUNCTION("fileSystem.chooseEntry", FILESYSTEM_CHOOSEENTRY)
 
   typedef std::vector<linked_ptr<extensions::api::file_system::AcceptOption> >
       AcceptOptions;
 
   static void BuildFileTypeInfo(
       ui::SelectFileDialog::FileTypeInfo* file_type_info,
       const base::FilePath::StringType& suggested_extension,
       const AcceptOptions* accepts,
@@ skipping 14 matching lines @@
 
  private:
   // FileSelected and FileSelectionCanceled are called by the file picker.
   void FileSelected(const base::FilePath& path, EntryType entry_type);
   void FileSelectionCanceled();
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_API_FILE_SYSTEM_FILE_SYSTEM_API_H_