Fix filesystem API file_handlers to work for drive on ChromeOS.

webkit/chromeos/fileapi/cros_mount_point_provider.h

Index: webkit/chromeos/fileapi/cros_mount_point_provider.h
diff --git a/webkit/chromeos/fileapi/cros_mount_point_provider.h b/webkit/chromeos/fileapi/cros_mount_point_provider.h
index 9c9723843ecd54f087bb9e9a766494e8c1034c1b..3d6fedaa95d96be1d44ee39426a32a5211c666b7 100644
--- a/webkit/chromeos/fileapi/cros_mount_point_provider.h
+++ b/webkit/chromeos/fileapi/cros_mount_point_provider.h
@@ -97,11 +97,18 @@ class WEBKIT_STORAGE_EXPORT CrosMountPointProvider
   virtual void RevokeAccessForExtension(
       const std::string& extension_id) OVERRIDE;
   virtual bool GetVirtualPath(const base::FilePath& filesystem_path,
-                              base::FilePath* virtual_path) OVERRIDE;
+                              base::FilePath* virtual_path) const OVERRIDE;
 
  private:
+  // If |original| is isolated filesystem URL, returns filesystem URL with the
+  // same path (as FileSystemURL::path()), but mapped by available external
+  // mount points.
+  // If the original filesystem URL already is external filesystem URL, returns
+  // |original|.
+  fileapi::FileSystemURL GetAsExternalFileSystemURL(
+      const fileapi::FileSystemURL& original) const;
   fileapi::RemoteFileSystemProxyInterface* GetRemoteProxy(
-      const std::string& mount_name) const;
+      const fileapi::FileSystemURL& url) const;
 
   scoped_refptr<quota::SpecialStoragePolicy> special_storage_policy_;
   scoped_ptr<FileAccessPermissions> file_access_permissions_;