ChromeOS: Implement MediaTransferProtocolManager observer.

chrome/browser/system_monitor/media_transfer_protocol_device_observer_chromeos.h

+// 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.
+
+#ifndef CHROME_BROWSER_SYSTEM_MONITOR_MEDIA_TRANSFER_PROTOCOL_DEVICE_OBSERVER_CHROMEOS_H_
+#define CHROME_BROWSER_SYSTEM_MONITOR_MEDIA_TRANSFER_PROTOCOL_DEVICE_OBSERVER_CHROMEOS_H_
+
+#include <map>
+#include <string>
+
+#include "base/string16.h"
+#include "chrome/browser/chromeos/mtp/media_transfer_protocol_manager.h"
+
+namespace chromeos {
+namespace mtp {
+
+// Gets the mtp device information given a |storage_name|. On success,
+// fills in |id|, |name| and |location|.
+typedef void (*GetStorageInfoFunc)(const std::string& storage_name,
+                                   std::string* id,
+                                   string16* name,
+                                   std::string* location);
+
+// Helper class to send MTP storage attachment and detachment events to
+// SystemMonitor.
+class MediaTransferProtocolDeviceObserverCros
+    : public MediaTransferProtocolManager::Observer {
+ public:
+  MediaTransferProtocolDeviceObserverCros();
+  virtual ~MediaTransferProtocolDeviceObserverCros();
+
+ protected:
+  // Only used in unit tests.
+  explicit MediaTransferProtocolDeviceObserverCros(
+      GetStorageInfoFunc get_storage_info_func);
+
+  // MediaTransferProtocolManager::Observer implementation.
+  // Exposed for unit tests.
+  virtual void StorageChanged(bool is_attached,
+                              const std::string& storage_name) OVERRIDE;
+
+ private:
+  // Mapping of storage name and device id.
+  typedef std::map<std::string, std::string> StorageNameToIdMap;
+
+  // Enumerate existing mtp storage devices.
+  void EnumerateStorages();
+
+  // Map of all attached mtp devices.
+  StorageNameToIdMap storage_map_;
+
+  // Function handler to get storage information. This is useful to set a mock
+  // handler for unit testing.
+  GetStorageInfoFunc get_storage_info_func_;
+
+  DISALLOW_COPY_AND_ASSIGN(MediaTransferProtocolDeviceObserverCros);
+};
+
+}  // namespace mtp
+}  // namespace chromeos
+
+#endif  // CHROME_BROWSER_SYSTEM_MONITOR_MEDIA_TRANSFER_PROTOCOL_DEVICE_OBSERVER_CHROMEOS_H_