The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/29e9989bdde19978fc9e7b92b1c762f99d8b2cd5

commit 29e9989bdde19978fc9e7b92b1c762f99d8b2cd5
Author: lawrencewu <lawrencewu@chromium.org>
Date: Wed Nov 09 23:08:47 2016

Bump field trial allocator size to 64kb and report usage

This CL changes the size of the shared memory used by the field trial allocator
to 64kb from 4kb, since 4kb was too small and was causing crashes. It also now
correctly reports the used size of the allocator in a histogram.

BUG= 663415 

Review-Url: https://codereview.chromium.org/2490513004
Cr-Commit-Position: refs/heads/master@{#431071}

[modify] https://crrev.com/29e9989bdde19978fc9e7b92b1c762f99d8b2cd5/base/metrics/field_trial.cc
[modify] https://crrev.com/29e9989bdde19978fc9e7b92b1c762f99d8b2cd5/tools/metrics/histograms/histograms.xml