Polish the SystemInfoProvider template code and refactor StorageInfoProvider based on it

chrome/browser/extensions/api/system_info_storage/storage_info_provider_mac.cc

Index: chrome/browser/extensions/api/system_info_storage/storage_info_provider_mac.cc
diff --git a/chrome/browser/extensions/api/system_info_storage/storage_info_provider_mac.cc b/chrome/browser/extensions/api/system_info_storage/storage_info_provider_mac.cc
new file mode 100644
index 0000000000000000000000000000000000000000..2c7f555b15a7f29997d97bb1964af1600173511d
--- /dev/null
+++ b/chrome/browser/extensions/api/system_info_storage/storage_info_provider_mac.cc
@@ -0,0 +1,42 @@
+// Copyright (c) 2012 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 "chrome/browser/extensions/api/system_info_storage/storage_info_provider.h"
+
+namespace extensions {
+
+namespace {
+
+using api::experimental_system_info_storage::StorageInfo;
+using api::experimental_system_info_storage::StorageUnitInfo;
+
+// StorageInfoProvider implementation on Macdows platform.
+// TODO(hongbo): not implemented yet.
+class StorageInfoProviderMac : public StorageInfoProvider {
+ public:
+  StorageInfoProviderMac() {}
+  virtual ~StorageInfoProviderMac() {}
+
+  virtual bool QueryInfo(StorageInfo* info) OVERRIDE;
+  virtual bool QueryUnitInfo(const std::string& id,
+                             StorageUnitInfo* info) OVERRIDE;
+};
+
+bool StorageInfoProviderMac::QueryInfo(StorageInfo* info) {
+  return false;
+}
+
+bool StorageInfoProviderMac::QueryUnitInfo(const std::string& id,
+                                           StorageUnitInfo* info) {
+  return false;
+}
+
+}  // namespace
+
+// static
+StorageInfoProvider* StorageInfoProvider::Get() {
+  return StorageInfoProvider::GetInstance<StorageInfoProviderMac>();
+}
+
+}  // namespace extensions