Expose data uri parsing to the HLS parser
Expose data uri parsing to the HLS parser

Widevine HLS manifests have a data URI that needs to be parsed to
generate DrmInfo.  Rather than write another parser, factor the data
URI networking plugin to expose the parser to other classes.

Issue #279

Change-Id: I71f174b86cc3b0ae0e8dbc31701ea9d36cd157ee

TheModMaker/shaka-player,brightcove/shaka-player,tvoli/shaka-player,TheModMaker/shaka-player,indiereign/shaka-player,russitto/shaka-player,tvoli/shaka-player,vimond/shaka-player,Ross-cz/shaka-player,TheModMaker/shaka-player,Ross-cz/shaka-player,shaka-project/shaka-player,brightcove/shaka-player,shaka-project/shaka-player,tvoli/shaka-player,brightcove/shaka-player,vimond/shaka-player,shaka-project/shaka-player,TheModMaker/shaka-player,vimond/shaka-player,tvoli/shaka-player,russitto/shaka-player,russitto/shaka-player,indiereign/shaka-player,shaka-project/shaka-player,indiereign/shaka-player,Ross-cz/shaka-player