Roll external/skia 1315333b6..005fdd4ec (8 commits)

https://skia.googlesource.com/skia.git/+log/1315333b6..005fdd4ec

2018-11-15 skia-autoroll@skia-public.iam.gserviceaccount.com Roll third_party/externals/swiftshader 3fc6893c8b24..8f20452b0219 (1 commits)
2018-11-15 skia-autoroll@skia-public.iam.gserviceaccount.com Roll third_party/externals/angle2 f3acb8c133fa..666818eacf79 (1 commits)
2018-11-15 csmartdalton@google.com sksl: Add support for 2x2 matrix inversions in Metal
2018-11-15 egdaniel@google.com Add flag to force purge resources from cache as soon as possible.
2018-11-15 mtklein@google.com remove mention of 16-bit shader procs
2018-11-15 brianosman@google.com Use GrVertexWriter in GrLatticeOp
2018-11-15 caryclark@skia.org bookmaker does deprecated
2018-11-15 mtklein@google.com lookup received factories directly

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Change-Id: Ia8e5adc710fa140d765693d5ba6e2002eed47580
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