Remove MTP support on Linux.

components/storage_monitor/test_storage_monitor.h

 // 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.
 
 #ifndef COMPONENTS_STORAGE_MONITOR_TEST_STORAGE_MONITOR_H_
 #define COMPONENTS_STORAGE_MONITOR_TEST_STORAGE_MONITOR_H_
 
 #include <memory>
 #include <string>
 
@@ skipping 28 matching lines @@
   bool GetStorageInfoForPath(const base::FilePath& path,
                              StorageInfo* device_info) const override;
 
 #if defined(OS_WIN)
   bool GetMTPStorageInfoFromDeviceId(
       const std::string& storage_device_id,
       base::string16* device_location,
       base::string16* storage_object_id) const override;
 #endif
 
-#if defined(OS_LINUX)
+#if defined(OS_CHROMEOS)
   device::MediaTransferProtocolManager* media_transfer_protocol_manager()
       override;
 #endif
 
   Receiver* receiver() const override;
 
   void EjectDevice(
       const std::string& device_id,
       base::Callback<void(StorageMonitor::EjectStatus)> callback) override;
 
   const std::string& ejected_device() const { return ejected_device_; }
 
   void AddRemovablePath(const base::FilePath& path);
 
   bool init_called() const { return init_called_; }
 
  private:
   // Whether TestStorageMonitor::Init() has been called for not.
   bool init_called_;
 
   // The last device to be ejected.
   std::string ejected_device_;
 
   // Paths considered for testing purposes to be on removable storage.
   std::vector<base::FilePath> removable_paths_;
 
-#if defined(OS_LINUX)
+#if defined(OS_CHROMEOS)
   std::unique_ptr<device::MediaTransferProtocolManager>
       media_transfer_protocol_manager_;
 #endif
 };
 
 }  // namespace storage_monitor
 
 #endif  // COMPONENTS_STORAGE_MONITOR_TEST_STORAGE_MONITOR_H_