The Tor Browser: gfx/skia/README

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

     1 The source from this directory was copied from the skia subversion trunk

     2 using the update.sh script. The changes made were those applied by update.sh,

     3 the addition/update of Makefile.in files for the Mozilla build system.

     5 The subversion revision used was r13827.

     7 To update to a new version of Skia:

     9 - Copy the entire trunk/ directory from a Skia clone to mozilla-central/gfx/skia

    10 - cd gfx/skia && ./gyp_mozbuild

    12 Once that's done, use git status to view the files that have changed. Keep an eye on GrUserConfig.h

    13 and SkUserConfig.h as those probably don't want to be overwritten by upstream versions.

    15 This process will be made more automatic in the future.

The Tor Browser / file revision