Remove memory peak detection code.

This CL removes dead code. It has no intended behavior change.

Change-Id: I5f5cabb2e162da82777a168df191c14fd0f9a295
Bug: 847876
TBR: dpranke@chromium.org
Reviewed-on: https://chromium-review.googlesource.com/1076506
Commit-Queue: Erik Chen <erikchen@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: Siddhartha S <ssid@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#562836}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 6b9b0c9cc512ffe6b6dad9f37f32186a44756cb5