Make ClientRectList.item() argument mandatory and drop [IsIndex]

Make ClientRectList.item() argument mandatory and drop [IsIndex]

Make ClientRectList.item() argument mandatory and drop [IsIndex] IDL extended
attribute to match the latest specification:
http://dev.w3.org/csswg/cssom-view/#dom-clientrectlist-item

According to the specification, the index argument for ClientRectList.item() is
mandatory and we should not throw when the index is negative, as long as it
wraps to a valid index value (when calling toUInt32() as per Web IDL
specification).

Our new behavior is consistent with Firefox 22 as well. Note however that IE10
behaves differently: the argument is optional and passing a negative index
throws even if it wraps to a valid index.

Note that according to the specification, we should throw an IndexSizeError
exception when index is greater than the number of ClientRect objects associated
with the object. Blink just returns null in this case and this patch does not
change this behavior as it is consistent with Firefox 22. IE10 does throw in
this case though.

BUG=237739
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=155588

[haraken, 2013-08-05 12:43:42]

What about Opera?

[do-not-use, 2013-08-05 12:52:54]

On 2013/08/05 12:43:42, haraken wrote:
> What about Opera?

Isn't Opera using Blink now? Or do you want me to test an older version using
Presto?

[haraken, 2013-08-05 12:56:27]

On 2013/08/05 12:52:54, Christophe Dumez wrote:
> On 2013/08/05 12:43:42, haraken wrote:
> > What about Opera?
> 
> Isn't Opera using Blink now? Or do you want me to test an older version using
> Presto?

Right. I was stupid :)

LGTM, given the behavior of Firefox and the spec. Needs an approval from an API
reviewer.

[haraken, 2013-08-05 12:56:27]

On 2013/08/05 12:52:54, Christophe Dumez wrote:
> On 2013/08/05 12:43:42, haraken wrote:
> > What about Opera?
> 
> Isn't Opera using Blink now? Or do you want me to test an older version using
> Presto?

Right. I was stupid :)

LGTM, given the behavior of Firefox and the spec. Needs an approval from an API
reviewer.

[arv (Not doing code reviews), 2013-08-05 13:54:00]

LGTM

[tkent, 2013-08-05 22:31:39]

lgtm
IE10 behavior sounds unreasonable...

[commit-bot: I haz the power, 2013-08-06 06:30:10]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/ch.dumez@sisa.samsung.com/22191002/1

[commit-bot: I haz the power, 2013-08-06 08:05:59]

Change committed as 155588