Roll external/skia 4bc701180..e28f9c65f (24 commits)

https://skia.googlesource.com/skia.git/+log/4bc701180..e28f9c65f

2018-03-02 angle-skia-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com Roll skia/third_party/externals/angle2/ b7d145861..437664b4b (1 commit)
2018-03-02 robertphillips@google.com Make use of the buffer data null hint a GrContextOption
2018-03-02 angle-skia-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com Roll skia/third_party/externals/angle2/ d6fef528f..b7d145861 (1 commit)
2018-03-02 egdaniel@google.com Add ctor to GrVkAlloc
2018-03-01 halcanary@google.com SkString: remove externally unused ::setUTF16() from API
2018-03-01 scroggo@google.com Fix fuschia roll
2018-03-01 angle-skia-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com Roll skia/third_party/externals/angle2/ 98e6a5f7b..d6fef528f (1 commit)
2018-03-01 ethannicholas@google.com Fixed SkSL use-after-free fuzzer bug and added defensive code to catch such problems in the future.
2018-03-01 benjaminwagner@google.com Omit path_text_clipped_uncached for RadeonHD7770.
2018-03-01 egdaniel@google.com Move workaround for fSRGBsupport before config table init in GrVkCaps
2018-03-01 brianosman@google.com Revert "Add 1010102 support to Ganesh"
2018-03-01 robertphillips@google.com sk_sp-ify GrGlyphCache
2018-03-01 benjaminwagner@google.com Upgrade Windows Skolo NVIDIA GPU drivers.
2018-03-01 robertphillips@google.com Move atlas manager creation to GrContext derived classes (take 2)
2018-03-01 kjlubick@google.com [skpbench] experiment with not disabling services
2018-03-01 egdaniel@google.com Move the rest of Vulkan driver workarounds into helper function in GrVkCaps
2018-03-01 halcanary@google.com SkQP: new apk
2018-03-01 robertphillips@google.com Fission GrAtlasGlyphCache in two (take 2)
2018-03-01 halcanary@google.com SkString: fix ::setUTF16
2018-03-01 brianosman@google.com Add 1010102 support to Ganesh
2018-03-01 benjaminwagner@google.com Omit longpathdash on Chorizo to avoid OOM.
2018-03-01 halcanary@google.com SkQP/Doc: new apks
2018-03-01 egdaniel@google.com Add unit test the explicit tests create a GrVkCopyPipeline
2018-03-01 robertphillips@google.com Clean up GrDrawOpAtlas (take 2)

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Change-Id: Ia16612963a8b697d03a49562015e1d7bc1592354
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