quipper: PerfReader stores string metadata as proto

BUG=chromium:568870
TEST=unit tests pass

Change-Id: Iac14ef57f4e40d50026f254ef46e21b29ad0d483
Signed-off-by: Simon Que <sque@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/327295
Reviewed-by: David Sharp <dhsharp@chromium.org>
4 files changed