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

chromeos/dbus/shill_third_party_vpn_observer.h

 // 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.
 
 #ifndef CHROMEOS_DBUS_SHILL_THIRD_PARTY_VPN_OBSERVER_H_
 #define CHROMEOS_DBUS_SHILL_THIRD_PARTY_VPN_OBSERVER_H_
 
 #include <stdint.h>
-#include <string>
+#include <vector>
 
 namespace chromeos {
 
 // This is a base class for observers which handle signals sent by the
 // ThirdPartyVpnAdaptor in Shill.
 class ShillThirdPartyVpnObserver {
  public:
-  virtual void OnPacketReceived(const std::string& data) = 0;
+  virtual void OnPacketReceived(const std::vector<char>& data) = 0;
   virtual void OnPlatformMessage(uint32_t message) = 0;
 
  protected:
   virtual ~ShillThirdPartyVpnObserver() {}
 
  private:
   DISALLOW_ASSIGN(ShillThirdPartyVpnObserver);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROMEOS_DBUS_SHILL_THIRD_PARTY_VPN_OBSERVER_H_