cc: Make the invalidation frequency buffer bigger.

cc: Make the invalidation frequency buffer bigger.

With large enough tiles we can get visible checkerboards if the buffer
we use for invalidation frequency is too small. Note that this fix
is a work around to make this case less likely to hit.

The proper fix is to stop repainting off screen frequently invalidating
content at a higher level.

R=enne, danakj
BUG=467197
Committed: https://crrev.com/ba84d9f7d200b847d5d6cefefa324f972f9541aa
Cr-Commit-Position: refs/heads/master@{#323838}

[vmpstr, 2015-04-03 21:10:57]

Please take a look.

[enne (OOO), 2015-04-03 21:13:16]

The CQ bit was checked by enne@chromium.org

[enne (OOO), 2015-04-03 21:13:16]

lgtm

[commit-bot: I haz the power, 2015-04-03 21:13:40]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1059403002/20001

[commit-bot: I haz the power, 2015-04-03 22:35:20]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-04-03 22:36:43]

Patchset 2 (id:??) landed as
https://crrev.com/ba84d9f7d200b847d5d6cefefa324f972f9541aa
Cr-Commit-Position: refs/heads/master@{#323838}