GitLab

Adds a simple cache with prime modulo hashing. This cache gets 95% hit
rate and gives us 30% performance improvement compared to without cache
for running heap profiler.

BUG=819888

Change-Id: I4c3dd6cf34ee1db21469e56886eaa3f62dd1881d
Reviewed-on: https://chromium-review.googlesource.com/985234Reviewed-by: Dmitry Skiba <dskiba@chromium.org>
Commit-Queue: Siddhartha S <ssid@chromium.org>
Cr-Commit-Position: refs/heads/master@{#548570}