Roll external/skia 0bd24dc41..be46e24d5 (14 commits)

https://skia.googlesource.com/skia.git/+log/0bd24dc41..be46e24d5

2018-01-16 halcanary@google.com Revert "Move resourceProvider accessor to GrContextPriv"
2018-01-16 angle-skia-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com Roll skia/third_party/externals/angle2/ cf180fccb..4747414ed (2 commits)
2018-01-16 angle-skia-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com Roll skia/third_party/externals/angle2/ dda048cdc..cf180fccb (1 commit)
2018-01-16 scroggo@google.com Add a method to convert SkCodec::Result to a string
2018-01-16 fmalita@chromium.org Fix Viewer slide load on backend change
2018-01-16 egdaniel@google.com Delete Gr testing contexts in reverse order
2018-01-16 brianosman@google.com Fix file loading from bundles on iOS
2018-01-16 ethannicholas@google.com request SPIR-V InputAttachment capability when needed
2018-01-16 robertphillips@google.com Move resourceProvider accessor to GrContextPriv
2018-01-16 robertphillips@google.com Fix FPs
2018-01-16 robertphillips@google.com Fix --preAbandonGpuContext bots
2018-01-16 brianosman@google.com Remove color space restrictions from GrBackendTextureImageGenerator
2018-01-16 brianosman@google.com Revert "Revert "Added SkSL workaround for devices which cannot safely access gl_FragCoord""
2018-01-16 bsalomon@google.com Don't apply coverage aa on image edges when target has msaa.

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Bug: 63909536
Change-Id: I8e8cd4e3d7c729414c3debd8a8c82c7f4135c31d