[ew] Add basic classes.

webkit/browser/fileapi/watcher_manager.h

Index: webkit/browser/fileapi/watcher_manager.h
diff --git a/webkit/browser/fileapi/watcher_manager.h b/webkit/browser/fileapi/watcher_manager.h
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+++ b/webkit/browser/fileapi/watcher_manager.h
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+// 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 WEBKIT_BROWSER_FILEAPI_WATCHER_MANAGER_H_
+#define WEBKIT_BROWSER_FILEAPI_WATCHER_MANAGER_H_
+
+#include <vector>
+
+#include "base/basictypes.h"
+#include "base/callback_forward.h"
+#include "base/files/file.h"
+
+namespace base {
+class Time;
+}
+
+namespace storage {
+
+class FileSystemOperationContext;
+class FileSystemURL;
+
+// An interface for providing entry observing capability for file system
+// backends.
+//
+// It is NOT valid to give null callback to this class, and implementors
+// can assume that they don't get any null callbacks.
+class WatcherManager {
+ public:
+  typedef base::Callback<void(base::File::Error result)> StatusCallback;
+
+  // Observes watched entries.
+  class Observer {
+   public:
+    Observer() {}
+    virtual ~Observer() {}
+
+    // Notifies about an entry represented by |url| being changed.
+    virtual void OnEntryChanged(const FileSystemURL& url) = 0;
+
+    // Notifies about an entry represented by |url| being removed.
+    virtual void OnEntryRemoved(const FileSystemURL& url) = 0;
+  };
+
+  virtual ~WatcherManager() {}
+
+  virtual void AddObserver(Observer* observer) = 0;
+  virtual void RemoveObserver(Observer* observer) = 0;
+  virtual bool HasObserver(Observer* observer) const = 0;
+
+  // Observes a directory entry. If the |recursive| mode is not supported then
+  // FILE_ERROR_INVALID_OPERATION must be returned as an error. If the |url| is
+  // already watched, or setting up the watcher fails, then |callback|
+  // must be called with a specific error code. Otherwise |callback| must be
+  // called with the FILE_OK error code.
+  virtual void WatchDirectory(const FileSystemURL& url,
+                              bool recursive,
+                              const StatusCallback& callback) = 0;
+
+  // Stops observing an entry represented by |url|.
+  virtual void UnwatchEntry(const FileSystemURL& url,
+                            const StatusCallback& callback) = 0;
+};
+
+}  // namespace storage
+
+#endif  // WEBKIT_BROWSER_FILEAPI_WATCHER_MANAGER_H_