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This makes some test output more readable. I've added the implementations
to the test_support library so we don't accidentally link these
functions into Chrome. The definitions are included alongside the types
being printed, opposed to a test support header file, to avoid ODR violations

Change-Id: Ica0aa9629f9cf745b0a4e42b3536d9537b34bfc7
Reviewed-on: https://chromium-review.googlesource.com/1101472
Commit-Queue: Dan H <harringtond@chromium.org>
Reviewed-by: Carlos Knippschild <carlosk@chromium.org>
Reviewed-by: David Trainor <dtrainor@chromium.org>
Cr-Commit-Position: refs/heads/master@{#575666}