Make GPU_CLIENT_DCHECK_CODE_BLOCK obey DCHECK_ALWAYS_ON.

Note that this block of #ifdefs violates the indentation guidelines,
but I'm ignoring that because the current form is more readable.

BUG=714761
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.android:android_optional_gpu_tests_rel;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/2837773004
Cr-Commit-Position: refs/heads/master@{#466790}
1 file changed