clang/win: Let remaining chromium_code targets build with -Wextra.

win8/metro_driver/file_picker_ash.h

 // Copyright (c) 2013 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_UI_METRO_DRIVER_FILE_PICKER_ASH_H_
 #define CHROME_BROWSER_UI_METRO_DRIVER_FILE_PICKER_ASH_H_
 
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
@@ skipping 65 matching lines @@
                         const base::string16& title,
                         const base::string16& filter,
                         const base::FilePath& default_path,
                         bool allow_multi_select);
   ~OpenFilePickerSession() override;
 
   const std::vector<base::FilePath>& filenames() const {
     return filenames_;
   }
 
-  const bool allow_multi_select() const {
-    return allow_multi_select_;
-  }
+  bool allow_multi_select() const { return allow_multi_select_; }
 
  private:
   HRESULT StartFilePicker() override;
 
   typedef winfoundtn::IAsyncOperation<winstorage::StorageFile*>
       SingleFileAsyncOp;
   typedef winfoundtn::Collections::IVectorView<
       winstorage::StorageFile*> StorageFileVectorCollection;
   typedef winfoundtn::IAsyncOperation<StorageFileVectorCollection*>
       MultiFileAsyncOp;
@@ skipping 51 matching lines @@
       FolderPickerAsyncOp;
 
   // Called asynchronously when the folder picker is done.
   HRESULT FolderPickerDone(FolderPickerAsyncOp* async, AsyncStatus status);
 
   DISALLOW_COPY_AND_ASSIGN(FolderPickerSession);
 };
 
 #endif  // CHROME_BROWSER_UI_METRO_DRIVER_FILE_PICKER_ASH_H_