sync: Introduce CryptographerProvider interface

sync/engine/cryptographer_provider.cc

+// 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.
+
+#include "sync/engine/cryptographer_provider.h"
+
+namespace syncer {
+
+CryptographerProvider::CryptographerProvider() {
+}
+
+CryptographerProvider::~CryptographerProvider() {
+}
+
+ScopedCryptographer::ScopedCryptographer() {
+}
+
+ScopedCryptographer::~ScopedCryptographer() {
+}
+
+bool ScopedCryptographer::Initialize(ScopedCryptographerImpl* impl) {
+  scoped_cryptographer_impl_.reset(impl);
+  return IsValid();
+}
+
+bool ScopedCryptographer::IsValid() const {
+  return !!Get();
+}
+
+Cryptographer* ScopedCryptographer::Get() const {
+  if (!scoped_cryptographer_impl_)
+    return NULL;
+  return scoped_cryptographer_impl_->Get();
+}
+
+ScopedCryptographerImpl::ScopedCryptographerImpl() {
+}
+
+ScopedCryptographerImpl::~ScopedCryptographerImpl() {
+}
+};

[Nicolas Zea, 2014/07/24 22:16:42]

This is the close namespace right? Shouldn't that semicolon generate a compile
warning/error?

also nit: newline above and // namespace syncer

[rlarocque, 2014/07/24 22:23:13]

I think that was from a bad copy/paste.  Fixed.

Spurious semicolons seem to be allowed in C, even outside a block.  I guess that
makes sense.  One less thing to worry about when writing #define macros.