Save memory prefs to disks more often
Save memory prefs to disks more often

The goal is to reduce the window where it is possible that a crash of Chrome
will cause double counting of prior crashes.
This change records all the (hopefully consistent) memory-resident state of the
metrics service to disk as soon as we get an ack from UMA that a
log was received.
Without this, there is a possible gap between when the stats are copied
to a log, and sent, vs. when the (now) zeroed crash count is written to disk.


bug=1314946

r=evanm,petersont

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@543 0039d316-1c4b-4281-b951-d872f2087c98

adobe/chromium,Crystalnix/house-of-life-chromium,ropik/chromium,Crystalnix/house-of-life-chromium,gavinp/chromium,ropik/chromium,adobe/chromium,Crystalnix/house-of-life-chromium,adobe/chromium,yitian134/chromium,yitian134/chromium,gavinp/chromium,ropik/chromium,ropik/chromium,yitian134/chromium,adobe/chromium,gavinp/chromium,gavinp/chromium,gavinp/chromium,adobe/chromium,gavinp/chromium,Crystalnix/house-of-life-chromium,Crystalnix/house-of-life-chromium,gavinp/chromium,yitian134/chromium,yitian134/chromium,yitian134/chromium,yitian134/chromium,Crystalnix/house-of-life-chromium,adobe/chromium,ropik/chromium,Crystalnix/house-of-life-chromium,Crystalnix/house-of-life-chromium,Crystalnix/house-of-life-chromium,ropik/chromium,adobe/chromium,Crystalnix/house-of-life-chromium,Crystalnix/house-of-life-chromium,yitian134/chromium,yitian134/chromium,ropik/chromium,gavinp/chromium,gavinp/chromium,adobe/chromium,gavinp/chromium,adobe/chromium,ropik/chromium,yitian134/chromium,adobe/chromium,ropik/chromium,adobe/chromium