Remove BlobRegistry indirection since there is only one implementation.

BUG=

Review URL: https://chromiumcodereview.appspot.com/15851008

git-svn-id: svn://svn.chromium.org/blink/trunk@152746 bbb929c8-8fbe-4397-9dbb-9b2b20218538
    virtual void didReadMetadata(const WebKit::WebFileInfo& info)
    {
        ASSERT(m_callbacks);
        if (info.type != WebKit::WebFileInfo::TypeFile || info.length < 0)
            m_callbacks->didFail(WebKit::WebFileErrorInvalidState);
        else {
            OwnPtr<AsyncFileWriterChromium> asyncFileWriterChromium = adoptPtr(new AsyncFileWriterChromium(m_client));
            OwnPtr<WebKit::WebFileWriter> webFileWriter = adoptPtr(m_webFileSystem->createFileWriter(m_path, asyncFileWriterChromium.get()));
            asyncFileWriterChromium->setWebFileWriter(webFileWriter.release());
            m_callbacks->didCreateFileWriter(asyncFileWriterChromium.release(), info.length);
        }
        delete this;
    }

    virtual void didReadMetadata(const WebKit::WebFileInfo& info)
    {
        ASSERT(m_callbacks);
        if (info.type != WebKit::WebFileInfo::TypeFile || info.length < 0)
            m_callbacks->didFail(WebKit::WebFileErrorInvalidState);
        else {
            OwnPtr<AsyncFileWriterChromium> asyncFileWriterChromium = adoptPtr(new AsyncFileWriterChromium(m_client));
            OwnPtr<WebKit::WebFileWriter> webFileWriter = adoptPtr(m_webFileSystem->createFileWriter(m_path, asyncFileWriterChromium.get()));
            asyncFileWriterChromium->setWebFileWriter(webFileWriter.release());
            m_callbacks->didCreateFileWriter(asyncFileWriterChromium.release(), info.length);
        }
        delete this;
    }
