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This provides cheaper (in terms of compile time) alternatives for code
that just wants to do a few simple CHECKs without pulling in the full
weight of logging.h. On Linux, the preprocessed size of check.h and
check_op.h are 2% and 62% of logging.h, respectively.

Splitting the CHECK and CHECK_op macros out to separate files also
reduces the complexity of logging.h which has become very complicated.

As a bonus, the new implementation is leaner, causing a 3% local
compile-time reduction for the chrome target on Linux even though no
includes have been changed yet.

Bug: 1031540
Change-Id: If7aca321f077110bea0907e487d2e8d29a8c50fd
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2128112
Commit-Queue: Nico Weber <thakis@chromium.org>
Reviewed-by: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#758287}