Set correct internalformat info for TexStorageEXT for WebGL1 context

WebGL1 context must behave like ES2 context, which crrev.com/2458103002 defines.

BUG=535198, 628064
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_optional_gpu_tests_rel;master.tryserver.chromium.mac:mac_optional_gpu_tests_rel;master.tryserver.chromium.win:win_optional_gpu_tests_rel

Review-Url: https://codereview.chromium.org/2548733002
Cr-Commit-Position: refs/heads/master@{#452718}
2 files changed