Roll external/skia ab865b088..e7e1d9d03 (5 commits)

https://skia.googlesource.com/skia.git/+log/ab865b088..e7e1d9d03

2017-05-02 jvanverth@google.com Fix up shadows in raster.
2017-05-02 egdaniel@google.com Make GrBackendTexture take Gr*Info refs in ctor, and copy them.
2017-05-02 brianosman@google.com Remove declaration of SkTextureImageSetTexture, which does not exist
2017-05-02 enne@chromium.org Expose resetForNextPicture in SkNoDrawCanvas
2017-05-02 msarett@google.com colorspaceinfo tool: Add flag to indicate that the input is an icc profile

Test: Presubmit checks will test this change.
Change-Id: Ibd818a2b3a59cf43f9d8d56fc83724c96c55cb8e