Use [TreatNullAs=EmptyString] for HTMLInputElement.value

Use [TreatNullAs=EmptyString] for HTMLInputElement.value

This is what the specification has. Previous behavior for setting the
value IDL attribute to null was effectively to reset the form control's
value to the default, which is wrong.

New behavior also matches that of Firefox and Opera/Presto.

BUG=391194
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=177564

[Jens Widell, 2014-07-05 09:42:09]

PTAL

[haraken, 2014-07-05 09:45:18]

LGTM

You could also mention that Firefox also aligns with the behavior in the CL
description.

https://codereview.chromium.org/372543002/diff/20001/LayoutTests/fast/dom/HTM...
File LayoutTests/fast/dom/HTMLInputElement/input-value-null.html (right):

https://codereview.chromium.org/372543002/diff/20001/LayoutTests/fast/dom/HTM...
LayoutTests/fast/dom/HTMLInputElement/input-value-null.html:17: test(function ()

Nit: No style guide for JavaScript, but Blink normally doesn't indent here.

https://codereview.chromium.org/372543002/diff/20001/LayoutTests/fast/dom/HTM...
LayoutTests/fast/dom/HTMLInputElement/input-value-null.html:18: {

Nit: Ditto.

test(function() {
    ...;
});

[Jens Widell, 2014-07-05 09:57:45]

Thanks for awesomely quick review!

Testcase style fixed, and description extended as suggested.

[Jens Widell, 2014-07-05 13:27:30]

The CQ bit was checked by jl@opera.com

[commit-bot: I haz the power, 2014-07-05 13:28:01]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/jl@opera.com/372543002/40001

[commit-bot: I haz the power, 2014-07-05 14:30:43]

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

[commit-bot: I haz the power, 2014-07-05 14:51:39]

Change committed as 177564