Roll external/skia 876cbbd72..8fa3a0c7b (3 commits)

https://skia.googlesource.com/skia.git/+log/876cbbd72..8fa3a0c7b

Test: Presubmit checks will test this change.
Bug: 36905374, 32984164
Test: CtsGraphicsTestCases
Change-Id: Ic60e4a92fb4e4529ff02383ed0a60eab1a1c6a2e