GitLab

This change reduces the number of usage cache update on appending data to a file, and improves the write performance from 75.72 MB/s (σ = 23.255) to 229.238 MB/s (σ = 31.442) on a benchmark.

https://www.googledrive.com/host/0B0EZi1x_1MtFSnNRZy1nalVNdlk/append-write.html

BUG=166158

Review URL: https://codereview.chromium.org/11639037

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@175474 0039d316-1c4b-4281-b951-d872f2087c98