PostMessageTest: retire use of zero-argument port.postMessage().

PostMessageTest: retire use of zero-argument port.postMessage().

In testPostUnsupportedWebMessageToApp, avoid invoking postMessage()
without any arguments. At least one is required for
MessagePort.postMessage().

R=sgurun@chromium.org
BUG=339441
Committed: https://crrev.com/66e905bc98ee7f88a5e55a3c9c33cec47912983d
Cr-Commit-Position: refs/heads/master@{#321855}

[sof, 2015-03-23 19:49:22]

sigbjornf@opera.com changed reviewers:
+ hush@chromium.org, sgurun@chromium.org

[sof, 2015-03-23 19:49:23]

Please take a look - hope I got the reviewers right.. :)

We're trying to make postMessage() conform to spec --
https://codereview.chromium.org/1025203002/ -- and need to tweak this webview
test accordingly.

[sgurun-gerrit only, 2015-03-23 20:22:45]

On 2015/03/23 19:49:23, sof wrote:
> Please take a look - hope I got the reviewers right.. :)
> 
> We're trying to make postMessage() conform to spec --
> https://codereview.chromium.org/1025203002/ -- and need to tweak this webview
> test accordingly.

lgtm

[sof, 2015-03-23 20:58:46]

The CQ bit was checked by sigbjornf@opera.com

[commit-bot: I haz the power, 2015-03-23 20:59:54]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1003603004/1

[commit-bot: I haz the power, 2015-03-23 21:23:46]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-03-23 21:24:26]

Patchset 1 (id:??) landed as
https://crrev.com/66e905bc98ee7f88a5e55a3c9c33cec47912983d
Cr-Commit-Position: refs/heads/master@{#321855}