Use BlobCallback in toBlob instead of FileCallback

third_party/WebKit/Source/core/html/HTMLCanvasElement.idl

 /*
  * Copyright (C) 2006, 2008, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Torch Mobile (Beijing) Co. Ltd. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 35 matching lines @@
     // handled differently the return type could be changed to "RenderingContext?"
     // and the [CallWith=ScriptState] extended attribute removed.
     //
     [CallWith=ScriptState] any getContext(DOMString contextId, [PermissiveDictionaryConversion] optional CanvasContextCreationAttributes attributes);
 
     // Note: The arguments argument is variadic in the spec, but not here as
     // only one extra argument is actually used.
     // FIXME: type should not have a default value.
     [RaisesException] DOMString toDataURL(optional DOMString type = null, optional any arguments);
 
-    [RaisesException, CallWith=ScriptState, RuntimeEnabled=ExperimentalCanvasFeatures] void toBlob(FileCallback _callback, optional DOMString type = null, optional any arguments);
+    [RaisesException, CallWith=ScriptState, RuntimeEnabled=ExperimentalCanvasFeatures] void toBlob(BlobCallback _callback, optional DOMString type = null, optional any arguments);
 };