Add request header support for the Browser/WebView.

QSB can use this instead of POST to send the location
data. After QSB makes the switch, we should also
remove the POST_DATA intent which is hidden.

Add loadUrl(String url, HashMap extraHeaders) to
WebView so that the caller can send the extra http
headers.

Remove "inline:" as no one is using it and it is a
hidden feature.

Part 1 of 3-project checkin.