Sync Blob.close() behavior wrt updated spec.

Source/modules/filesystem/InspectorFileSystemAgent.cpp

 /*
  * Copyright (C) 2011, 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 452 matching lines @@
     toFileEntry(entry)->file(successCallback.release(), errorCallback.release());
 
     m_reader = FileReader::create(entry->filesystem()->executionContext());
     m_mimeType = MIMETypeRegistry::getMIMETypeForPath(entry->name());
 
     return true;
 }
 
 bool FileContentRequest::didGetFile(File* file)
 {
-    RefPtr<Blob> blob = file->slice(m_start, m_end);
+    RefPtr<Blob> blob = static_cast<Blob*>(file)->slice(m_start, m_end, IGNORE_EXCEPTION);
     m_reader->setOnload(this);
     m_reader->setOnerror(this);
 
     m_reader->readAsArrayBuffer(blob.get(), IGNORE_EXCEPTION);
     return true;
 }
 
 void FileContentRequest::didRead()
 {
     RefPtr<ArrayBuffer> buffer = m_reader->arrayBufferResult();
@@ skipping 233 matching lines @@
     for (LocalFrame* frame = m_page->mainFrame(); frame; frame = frame->tree().traverseNext()) {
         if (frame->document() && frame->document()->securityOrigin()->isSameSchemeHostPort(origin))
             return frame->document();
     }
 
     *error = "No frame is available for the request";
     return 0;
 }
 
 } // namespace WebCore