Remove explicit bounds check from CSSValueList::item

Remove explicit bounds check from CSSValueList::item

Currently CSSValueList::item does a bounds check and will return null if
the given index is out of range. This patch makes the interface slightly
more sane by removing the check, which is currently otherwise skipped by
calling itemWithoutBoundsCheck. Note that the vector access will perform
a bounds check (with release assert) anyway. The only caller where the
bounds check behaviour is useful is for the IDL binding so a separate
function itemWithBoundsCheck is created for this (already tested by
value-list-out-of-bounds-crash.html).

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=177064

[Timothy Loh, 2014-06-24 07:04:32]

A small clean-up

[alancutter (OOO until 2018), 2014-06-26 00:36:35]

lgtm with nit.

https://codereview.chromium.org/333163004/diff/1/Source/core/css/StylePropert...
File Source/core/css/StylePropertySerializer.cpp (right):

https://codereview.chromium.org/333163004/diff/1/Source/core/css/StylePropert...
Source/core/css/StylePropertySerializer.cpp:507: value = i < list->length() ?
list->item(i) : nullptr;
itemWithBoundsCheck()

[Timothy Loh, 2014-06-26 04:41:19]

The CQ bit was checked by timloh@chromium.org

[commit-bot: I haz the power, 2014-06-26 04:42:25]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/timloh@chromium.org/333163004/20001

[commit-bot: I haz the power, 2014-06-26 05:52:27]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  linux_blink_dbg on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/linux_blink_dbg/builds/1...)

[(do not use) timloh, 2014-06-27 03:39:49]

The CQ bit was unchecked by timloh@google.com

[Timothy Loh, 2014-06-27 03:40:13]

The CQ bit was checked by timloh@chromium.org

[commit-bot: I haz the power, 2014-06-27 03:41:30]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/timloh@chromium.org/333163004/20001

[commit-bot: I haz the power, 2014-06-27 04:42:54]

Change committed as 177064