Roll external/skia a12118320..133944a14 (11 commits)

https://skia.googlesource.com/skia.git/+log/a12118320..133944a14

2018-11-19 csmartdalton@google.com Add a dedicated Op for analytic round rects
2018-11-19 caryclark@skia.org font doc
2018-11-19 egdaniel@google.com Reland "Reland "Have a GrBackendFormat be stored on gpu proxies.""
2018-11-19 halcanary@google.com Fuzz: un-inline some code
2018-11-19 halcanary@google.com SkPDF: move font serialization over to new immediate mode.
2018-11-19 skia-autoroll@skia-public.iam.gserviceaccount.com Roll third_party/externals/angle2 fde74c078f77..8a0fb48a56d6 (2 commits)
2018-11-19 brianosman@google.com Use half floats for non-normalized color in GrTextureOp
2018-11-19 mtklein@google.com simplify nextRange(), fold in nextEnum()
2018-11-19 scroggo@google.com Generate Android Framework host-side Skia (linux)
2018-11-19 brianosman@google.com Add helpers to deal with byte vs. half-float vertex colors
2018-11-19 jvanverth@google.com Revert "Reland "Remove use of integers for atlas indexing""

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Bug: 118742766
Change-Id: Ifb78cb570db7468c9a8f5f96c15b5d0e5d8ca83b