Make MountPointProvider pluggable from outside webkit/fileapi

webkit/fileapi/file_system_mount_point_provider.h

 // Copyright (c) 2012 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_FILEAPI_FILE_SYSTEM_MOUNT_POINT_PROVIDER_H_
 #define WEBKIT_FILEAPI_FILE_SYSTEM_MOUNT_POINT_PROVIDER_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 25 matching lines @@
 // and specialized FileSystemFileUtil instance.
 class WEBKIT_STORAGE_EXPORT FileSystemMountPointProvider {
  public:
   // Callback for ValidateFileSystemRoot.
   typedef base::Callback<void(base::PlatformFileError error)>
       ValidateFileSystemCallback;
   typedef base::Callback<void(base::PlatformFileError error)>
       DeleteFileSystemCallback;
   virtual ~FileSystemMountPointProvider() {}
 
+  // Returns true if this mount point provider can handle |type|.
+  // One mount point provider may be able to handle multiple filesystem types.
+  virtual bool CanHandleType(FileSystemType type) const = 0;
+
   // Validates the filesystem for the given |origin_url| and |type|.
   // This verifies if it is allowed to request (or create) the filesystem
   // and if it can access (or create) the root directory of the mount point.
   // If |create| is true this may also create the root directory for
   // the filesystem if it doesn't exist.
   virtual void ValidateFileSystemRoot(
       const GURL& origin_url,
       FileSystemType type,
       bool create,
       const ValidateFileSystemCallback& callback) = 0;
@@ skipping 104 matching lines @@
         const std::string& extension_id) = 0;
   // Gets virtual path by known filesystem path. Returns false when filesystem
   // path is not exposed by this provider.
   virtual bool GetVirtualPath(const base::FilePath& file_system_path,
                               base::FilePath* virtual_path) = 0;
 };
 
 }  // namespace fileapi
 
 #endif  // WEBKIT_FILEAPI_FILE_SYSTEM_MOUNT_POINT_PROVIDER_H_