[CSS Grid Layout] Cache track breadth min/max content types

[CSS Grid Layout] Cache track breadth min/max content types

Profiling shows we repeatedly hit the GridLength isLength() method and
the is{Min,Max}Content() methods of the actual Length object. By
caching this information, which won't change until we set again the
grid lengths, we can improve the auto-grid-lots-of-data.html test by
about a 6% (39 runs/s -> 41.5 runs/s).

BUG=234211
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=160184

[Julien - ping for review, 2013-10-18 18:47:35]

lgtm

https://codereview.chromium.org/28053003/diff/1/Source/core/rendering/style/G...
File Source/core/rendering/style/GridTrackSize.h (right):

https://codereview.chromium.org/28053003/diff/1/Source/core/rendering/style/G...
Source/core/rendering/style/GridTrackSize.h:131: m_minTrackBreadthIsMaxContent =
minTrackBreadth().isLength() && minTrackBreadth().length().isMaxContent();
Nit: you could avoid some recomputation here by changing the order and reusing
one cached value:

m_minTrackBreadthIsMaxContent = minTrackBreadth().isLength() &&
minTrackBreadth().length().isMaxContent();
m_minTrackBreadthIsMinOrMaxContent = m_minTrackBreadthIsMaxContent ||
(minTrackBreadth().isLength() && minTrackBreadth().length().isMaxContent());

[commit-bot: I haz the power, 2013-10-21 15:51:18]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/xan@igalia.com/28053003/50001

[commit-bot: I haz the power, 2013-10-21 18:23:47]

Retried try job too often on win_blink_rel for step(s) webkit_tests
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=win_blink_...

[commit-bot: I haz the power, 2013-10-21 18:48:55]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/xan@igalia.com/28053003/50001

[commit-bot: I haz the power, 2013-10-21 22:17:24]

Retried try job too often on win_blink_rel for step(s) webkit_tests
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=win_blink_...

[commit-bot: I haz the power, 2013-10-22 07:13:01]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/xan@igalia.com/28053003/50001

[commit-bot: I haz the power, 2013-10-22 11:08:13]

Change committed as 160184