De-duplicate ranges information in persistent memory.
By having BucketRanges keep a reference to where the data can be found
in persistent memory, the existing de-dup of the BucketRanges object
also serves to avoid duplicating the data in persistent memory.
Simple testing shows allocated persistent histogram memory in the
browser is reduced by about 22%. This should be similar in all
processes though somewhat less as the number of histograms held goes
down.
BUG=705342
Review-Url: https://codereview.chromium.org/2794073002
Cr-Commit-Position: refs/heads/master@{#462897}
CrOS-Libchrome-Original-Commit: af1913582fdf411b2f7edc84189c78b1fb402a37
4 files changed