[Mac] address perf regressions on bots...

[Mac] address perf regressions on bots

This isn't the prettiest, but it should get the perf back where we want it.  If the file we're asked to exclude is in /var or /private, ignore it.  The problem on the bots is the TimeMachine prefs plist is growing unbounded as we keep adding 4 files each run for temporary profiles.  The load/modify/write gets slower with each addition.  This quick/dirty check to avoid that.  Since the original bug for the backup of this data is still open, I figure landing this is the right thing to do until that is fully addressed.

BUG=25959, 30002
TEST=page cycles, browser_tests all get back to being fast.  normal profiles still exclude the files listed in the first bug.

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=35382

[Mark Mentovai, 2009-12-30 16:51:59]

ooolgtm

http://codereview.chromium.org/523024/diff/1/2
File base/mac_util.mm (right):

http://codereview.chromium.org/523024/diff/1/2#newcode246
base/mac_util.mm:246: // being added.  Otherwise, as the exclude list growns the
bots slow down down
growns -> grows

slow down down -> slow down

http://codereview.chromium.org/523024/diff/1/2#newcode248
base/mac_util.mm:248: if ([filePath hasPrefix:@"/var/"] ||
I'd scope this more narrowly, to

/tmp/
/var/tmp/
/private/tmp/
/private/var/tmp/

or you could check the temporary directory and see if it's the prefix of the
path being added.

You can also say in the comment (if it's true?) that as a matter of Time Machine
policy, temporary directories are excluded from backups.