[Chrome OS] Construct device label and unique id using vendor and product details.

chromeos/disks/mock_disk_mount_manager.h

Index: chromeos/disks/mock_disk_mount_manager.h
diff --git a/chromeos/disks/mock_disk_mount_manager.h b/chromeos/disks/mock_disk_mount_manager.h
index 169f33dade98367ad67c71d530d81eec9e37e1c7..a8c14cbd6b5c8605568c9d953bae8dd1b420c3c2 100644
--- a/chromeos/disks/mock_disk_mount_manager.h
+++ b/chromeos/disks/mock_disk_mount_manager.h
@@ -52,7 +52,8 @@ class MockDiskMountManager : public DiskMountManager {
   // primarily for MediaDeviceNotificationsTest.
   void CreateDiskEntryForMountDevice(
       const DiskMountManager::MountPointInfo& mount_info,
-      const std::string& device_id);
+      const std::string& device_id,
+      const std::string& device_label);
 
   // Removes the fake disk entry associated with the mounted device. This
   // function is primarily for MediaDeviceNotificationsTest.