Use std::map to find correct index range Instead of iterating through every range to find the one we're looking for, instead put them all in a map and find them with that. This helps performance with index buffers that contain a bunch of different ranges. BUG= TEST= Review URL: http://codereview.appspot.com/4974051 git-svn-id: https://angleproject.googlecode.com/svn/trunk@742 736b8ea6-26fd-11df-bfd4-992fa37f6226