Change access mode of disk devices when mounting based on config.

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 a37f8a0562ba5269559bec19746403191d10a24a..ff57e4373ab775df70ea3fb2389c8d64d16d2f82 100644
--- a/chromeos/disks/mock_disk_mount_manager.h
+++ b/chromeos/disks/mock_disk_mount_manager.h
@@ -37,8 +37,12 @@ class MockDiskMountManager : public DiskMountManager {
                      const DiskMountManager::MountPointMap&(void));
   MOCK_METHOD2(EnsureMountInfoRefreshed,
                void(const EnsureMountInfoRefreshedCallback&, bool));
-  MOCK_METHOD4(MountPath, void(const std::string&, const std::string&,
-                               const std::string&, MountType));
+  MOCK_METHOD5(MountPath,
+               void(const std::string&,
+                    const std::string&,
+                    const std::string&,
+                    MountType,
+                    MountAccessMode));
   MOCK_METHOD3(UnmountPath, void(const std::string&,
                                  UnmountOptions,
                                  const DiskMountManager::UnmountPathCallback&));