json_schema_compiler: Use std::vector<char> for binary values.

chrome/browser/extensions/api/braille_display_private/stub_braille_controller.h

 // Copyright 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_EXTENSIONS_API_BRAILLE_DISPLAY_PRIVATE_STUB_BRAILLE_CONTROLLER_H_
 #define CHROME_BROWSER_EXTENSIONS_API_BRAILLE_DISPLAY_PRIVATE_STUB_BRAILLE_CONTROLLER_H_
 
 #include "chrome/browser/extensions/api/braille_display_private/braille_controller.h"
 
 namespace extensions {
 namespace api {
 namespace braille_display_private {
 
 // Stub implementation for the BrailleController interface.
 class StubBrailleController : public BrailleController {
  public:
   StubBrailleController();
   scoped_ptr<DisplayState> GetDisplayState() override;
-  void WriteDots(const std::string& cells) override;
+  void WriteDots(const std::vector<char>& cells) override;
   void AddObserver(BrailleObserver* observer) override;
   void RemoveObserver(BrailleObserver* observer) override;
 };
 
 }  // namespace braille_display_private
 }  // namespace api
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_API_BRAILLE_DISPLAY_PRIVATE_STUB_BRAILLE_CONTROLLER_H_