Simple rebaseline tool:  Add support for ANGLE, DirectWrite builders. Set svn mime type to image/png.
Simple rebaseline tool:  Add support for ANGLE, DirectWrite builders.
Set svn mime type to image/png.

Review URL: https://codereview.appspot.com/6820054

git-svn-id: e8541e15acce502a64c929015570ad1648e548cd@6199 2bbb7eff-a529-9590-31e7-b0007b416f81

Cue/skia,metajack/skia,metajack/skia,Cue/skia,Cue/skia,metajack/skia,metajack/skia,mrobinson/skia,mrobinson/skia,mrobinson/skia,mrobinson/skia,Cue/skia,mrobinson/skia