input[type=date] warns if specified string is invalid.

input[type=date] warns if specified string is invalid.

We show a console message if:
 - An invalid string is set to 'value' IDL attribute.
 - An invalid string is set to 'value' content attribute.
 - 'date' is set to 'type' attribute and existing 'value' content attribute is
   invalid.
 - 'date' is set to 'type' attribute and existing user-specified value is
   invalid.

BUG=397952
TEST=Update expectations of automated tests.

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=180341

[tkent, 2014-08-15 07:49:28]

Keishi, would you review this please?

[keishi, 2014-08-15 08:15:49]

LGTM

[tkent, 2014-08-15 08:24:37]

The CQ bit was checked by tkent@chromium.org

[commit-bot: I haz the power, 2014-08-15 08:25:19]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/tkent@chromium.org/461323006/20001

[commit-bot: I haz the power, 2014-08-15 08:47:00]

Committed patchset #1 (20001) as 180341