IDL: Add more test cases to idl-dictionary-unittest.html

IDL: Add more test cases to idl-dictionary-unittest.html

Add DictionaryHelper::getWithUndefinedOrNullCheck() to fix a bug that
newly added tests found. When IDL dictionary member is undefined or null,
the member should be treated as 'not present' and default values should
be used when specified. Since DictionaryHelper::get() converts
null/undefined into a valid value, we can't use DictionaryHelper::get()
in IDL dictionary implementation directly.

BUG=321462
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=181604

[bashi, 2014-09-09 04:01:24]

bashi@chromium.org changed reviewers:
+ haraken@chromium.org

[bashi, 2014-09-09 04:01:25]

Haraken-san, PTAL?

This is obsoleting https://codereview.chromium.org/508073002/. I'm working on
refactoring DictionaryHelper, but it takes some time so I'd like to fix the bug
beforehand.

[haraken, 2014-09-09 04:06:01]

LGTM.

[bashi, 2014-09-09 04:16:56]

The CQ bit was checked by bashi@chromium.org

[commit-bot: I haz the power, 2014-09-09 04:18:08]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/bashi@chromium.org/554893004/1

[commit-bot: I haz the power, 2014-09-09 05:02:27]

Committed patchset #1 (id:1) as 181604