Roll external/skia 9febd0b9f..35b40ce7a (6 commits)

https://skia.googlesource.com/skia.git/+log/9febd0b9f..35b40ce7a

2018-05-30 rmistry@google.com Revert "Check for ANGLE's implementation of texture_rectangle"
2018-05-30 swiftshader-skia-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com Roll third_party/externals/swiftshader 45fcfe8..9dfb70f (1 commits)
2018-05-30 reed@google.com 3d
2018-05-30 brianosman@google.com Clean up GPU configs in DM
2018-05-30 weiliangc@chromium.org Check for ANGLE's implementation of texture_rectangle
2018-05-30 egdaniel@google.com Use GrVkMemoryAllocator for vulkan memory allocations in ganesh.

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Change-Id: I51f73b8f1f637bcd5d0d6b987a3b3509fbdb8610
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