Rename CalledOnValidSequencedThread() to CalledOnValidSequence().

The new name is more accurate (we don't verify that we're on a
specific thread) and shorter.

Discussion here:
https://codereview.chromium.org/2165663003/diff/260001/base/sequence_checker.h#newcode25

TBR=jochen@chromium.org
BUG=
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/2189113002
Cr-Commit-Position: refs/heads/master@{#408558}
39 files changed