Defer ARC file system operations while ARC is booting.

components/arc/file_system/arc_file_system_operation_runner.h

Index: components/arc/file_system/arc_file_system_operation_runner.h
diff --git a/components/arc/file_system/arc_file_system_operation_runner.h b/components/arc/file_system/arc_file_system_operation_runner.h
new file mode 100644
index 0000000000000000000000000000000000000000..985ce0da7531e9b3401a63627745d72e3fc2b475
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+++ b/components/arc/file_system/arc_file_system_operation_runner.h
@@ -0,0 +1,55 @@
+// 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.
+
+#ifndef COMPONENTS_ARC_FILE_SYSTEM_ARC_FILE_SYSTEM_OPERATION_RUNNER_H_
+#define COMPONENTS_ARC_FILE_SYSTEM_ARC_FILE_SYSTEM_OPERATION_RUNNER_H_
+
+#include <string>
+
+#include "components/arc/arc_service.h"
+#include "components/arc/common/file_system.mojom.h"
+
+class GURL;
+
+namespace arc {
+
+// An interface to run ARC file system operations.
+//
+// This is an abstraction layer on top of mojom::FileSystemInstance.
+// In production, ArcDeferredFileSystemOperationRunner is always used which
+// defers file system operations while ARC is booting.
+// In unit tests, fake implementations will be injected.
+//
+// All member functions must be called on the UI thread.
+class ArcFileSystemOperationRunner : public ArcService {
+ public:
+  // For supporting ArcServiceManager::GetService<T>().
+  static const char kArcServiceName[];
+
+  explicit ArcFileSystemOperationRunner(ArcBridgeService* bridge_service);
+  ~ArcFileSystemOperationRunner() override;
+
+  using GetFileSizeCallback = mojom::FileSystemInstance::GetFileSizeCallback;
+  using OpenFileToReadCallback =
+      mojom::FileSystemInstance::OpenFileToReadCallback;
+  using GetDocumentCallback = mojom::FileSystemInstance::GetDocumentCallback;
+  using GetChildDocumentsCallback =
+      mojom::FileSystemInstance::GetChildDocumentsCallback;
+
+  // Runs file system operations. See file_system.mojom for documentation.
+  virtual void GetFileSize(const GURL& url,
+                           const GetFileSizeCallback& callback) = 0;
+  virtual void OpenFileToRead(const GURL& url,
+                              const OpenFileToReadCallback& callback) = 0;
+  virtual void GetDocument(const std::string& authority,
+                           const std::string& document_id,
+                           const GetDocumentCallback& callback) = 0;
+  virtual void GetChildDocuments(const std::string& authority,
+                                 const std::string& parent_document_id,
+                                 const GetChildDocumentsCallback& callback) = 0;
+};
+
+}  // namespace arc
+
+#endif  // COMPONENTS_ARC_FILE_SYSTEM_ARC_FILE_SYSTEM_OPERATION_RUNNER_H_