Restore old title in WebViewPlugin only when loading the plugin.

BUG=72437
TEST=see bug for manual test

Review URL: http://codereview.chromium.org/6476006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@74428 0039d316-1c4b-4281-b951-d872f2087c98
void WebViewPlugin::didFailLoading(const WebURLError& error) {
  DCHECK(!error_.get());
  error_.reset(new WebURLError(error));
}

void WebViewPlugin::didFailLoading(const WebURLError& error) {
  DCHECK(!error_.get());
  error_.reset(new WebURLError(error));
}
