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This CL is adding a trace events to debug some failures happening in the
field. An instant event will be present with an error code.

R=wittman@chromium.org
BUG=882982

Change-Id: I0a55ca82c4312bb212a5b7d1f3e391b42d3d38c9
Reviewed-on: https://chromium-review.googlesource.com/c/1297065
Commit-Queue: Etienne Bergeron <etienneb@chromium.org>
Reviewed-by: Mike Wittman <wittman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#602397}