cc: Optimize OnePriorityRectIterator a little bit.

cc: Optimize OnePriorityRectIterator a little bit.

This is a pretty small optimization, but it saves a few struct
copies, which seems to make a small difference (~1% improvement) in a
targeted perftest that runs this function.

R=enne
BUG=488636
Committed: https://crrev.com/1172ff24a17ca9e8d0778cf1ab277a8ddb38558d
Cr-Commit-Position: refs/heads/master@{#330637}

[vmpstr, 2015-05-19 20:05:56]

Please take a look. The improvement from this is very minor. A test that
basically hammers this function _seems_ to improve by about 1%. When translated
to end-to-end performance improvement, this is probably negligible. With that,
feel free to say "meh"

[vmpstr, 2015-05-19 20:29:28]

On 2015/05/19 20:05:56, vmpstr wrote:
> Please take a look. The improvement from this is very minor. A test that
> basically hammers this function _seems_ to improve by about 1%. When
translated
> to end-to-end performance improvement, this is probably negligible. With that,
> feel free to say "meh"

Actually, I changed the perftest to have all tiles initialized (worst case for
this iteration) and the number of times we can create the tiling set raster
iterator improves by about 17%, so maybe this is actually makes a noticeable
end-to-end change.

[enne (OOO), 2015-05-19 21:35:42]

The CQ bit was checked by enne@chromium.org

[enne (OOO), 2015-05-19 21:35:43]

lgtm

[commit-bot: I haz the power, 2015-05-19 21:38:09]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1130343005/1

[commit-bot: I haz the power, 2015-05-19 22:32:33]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-05-19 22:34:01]

Patchset 1 (id:??) landed as
https://crrev.com/1172ff24a17ca9e8d0778cf1ab277a8ddb38558d
Cr-Commit-Position: refs/heads/master@{#330637}