blink: Remove unused or rarely used methods from WebGraphicsContext3D
This is toward deleting the class entirely. These methods were not used
at all, or for a couple of them, had one caller which we redirect to the
GLES2Interface directly.
Adds a DEPS entry for core/testing/ to use GLES2Interface as there's
code in there calling things on WebGraphicsContext3D now.
R=kbr,esprehn,sievers,chrishtr
BUG=
584497
CQ_INCLUDE_TRYBOTS=tryserver.chromium.win:win_optional_gpu_tests_rel;tryserver.chromium.mac:mac_optional_gpu_tests_rel
Committed:
https://crrev.com/5260676ed275358c7b44da823b97bc1084c7a25e
Cr-Commit-Position: refs/heads/master@{#381586}