Merge third_party/skia/gyp from https://chromium.googlesource.com/external/skia/gyp.git at 6e773af83fe08119bdb50d8b720fcd46eebea74e

This commit was generated by merge_from_chromium.py.

Change-Id: If6846e005da93ea649ffe23122e2a934420eeadc