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
void BlobRegistryProxy::registerBlobURL(const KURL& url, const KURL& srcURL)
{
    if (m_webBlobRegistry)
        m_webBlobRegistry->registerBlobURL(url, srcURL);
}

void BlobRegistryProxy::registerBlobURL(const KURL& url, const KURL& srcURL)
{
    if (m_webBlobRegistry)
        m_webBlobRegistry->registerBlobURL(url, srcURL);
}
