Switch to standard integer types in components/, part 3 of 4.

components/proximity_auth/fake_secure_context.cc

 // Copyright 2015 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.
 
+#include <stddef.h>
+
 #include "components/proximity_auth/fake_secure_context.h"
 
 namespace proximity_auth {
 
 namespace {
 const char kFakeEncodingSuffix[] = ", but encoded";
 const char kChannelBindingData[] = "channel binding data";
 }  // namespace
 
 FakeSecureContext::FakeSecureContext()
@@ skipping 22 matching lines @@
           kFakeEncodingSuffix) {
     callback.Run(std::string());
   }
 
   std::string decoded_message = encoded_message;
   decoded_message.erase(decoded_message.rfind(kFakeEncodingSuffix));
   callback.Run(decoded_message);
 }
 
 }  // namespace proximity_auth