Move ExtensionCache to //extensions

extensions/browser/updater/null_extension_cache.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 "extensions/browser/updater/null_extension_cache.h"
+
+#include "base/callback.h"
+
+namespace extensions {
+
+NullExtensionCache::NullExtensionCache() {
+}
+
+NullExtensionCache::~NullExtensionCache() {
+}
+
+void NullExtensionCache::Start(const base::Closure& callback) {
+  callback.Run();
+}
+
+void NullExtensionCache::Shutdown(const base::Closure& callback) {
+  callback.Run();
+}
+
+void NullExtensionCache::AllowCaching(const std::string& id) {
+}
+
+bool NullExtensionCache::GetExtension(const std::string& id,
+                                      base::FilePath* file_path,
+                                      std::string* version) {
+  return false;
+}
+
+void NullExtensionCache::PutExtension(const std::string& id,
+                                      const base::FilePath& file_path,
+                                      const std::string& version,
+                                      const PutExtensionCallback& callback) {
+  callback.Run(file_path, true);
+}
+
+}  // namespace extensions