Merge third_party/skia/gyp from https://chromium.googlesource.com/external/skia/gyp.git at b460a213ddebe85e7a61996298582eff269b6f25

This commit was generated by merge_from_chromium.py.

Change-Id: I55909d3dce204a8700c4251abc0102bbd6f82f7a