Convert utility process ImageWriter IPC to mojo

chrome/common/extensions/removable_storage_writer.mojom

+// Copyright 2017 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.
+
+// Removable storage writer interface provided by the utility process
+// and exposed by mojo policy to the chrome browser process.
+
+module extensions.mojom;
+
+import "mojo/common/file_path.mojom";
+
+interface RemovableStorageWriter {
+  const string kTestDevice = "chrome://test-removable-storage-writer";
+
+  // Writes the content of the source file to the target. The target
+  // file is restricted to removable drives by the utility process.
+  Write(mojo.common.mojom.FilePath source,
+        mojo.common.mojom.FilePath target,
+        RemovableStorageWriterClient client);
+
+  // Verifies that the contents of the source file was written to the
+  // target file. Again, the target is restricted to removable drives
+  // by the utility process.
+  Verify(mojo.common.mojom.FilePath source,
+         mojo.common.mojom.FilePath target,
+         RemovableStorageWriterClient client);
+};
+
+interface RemovableStorageWriterClient {
+  // Interface to the client used to report write or verify operation
+  // progress and completion status.
+  Progress(int64 progress);
+  Complete(string? error);
+};