Fix the leaks in TestHyphenatorMessageFilter::OnOpenDictionary().

Fix the leaks in TestHyphenatorMessageFilter::OnOpenDictionary().
This change deletes IPC messages received in TestHyphenatorMessageFilter::OnMessage() to delete HyphenatorMsg_SetDictionary messages sent by TestHyphenatorMessageFilter::OnOpenDictionary().

BUG=146222
TEST=the memory bots are green without suppressions.

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=154900

[Hironori Bono, 2012-09-04 08:23:24]

Greetings John and Avi,

Unfortunately, my r154663 <http://crrev.com/154663> forgot deleting IPC messages
in its unit test and it causes several leaks. Would it be possible to review
this fix? (Technically, this change adds a 'delete' operator to my unit test.)
Thank you for your review in advance.

Regards,

Hironori Bono

[jam, 2012-09-04 17:01:54]

lgtm

[commit-bot: I haz the power, 2012-09-05 02:45:43]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/hbono@chromium.org/10907045/1

[commit-bot: I haz the power, 2012-09-05 02:45:47]

Failed to apply patch for tools/valgrind/memcheck/suppressions.txt:
While running patch -p0 --forward --force;
patching file tools/valgrind/memcheck/suppressions.txt
Hunk #1 FAILED at 5972.
1 out of 1 hunk FAILED -- saving rejects to file
tools/valgrind/memcheck/suppressions.txt.rej

[commit-bot: I haz the power, 2012-09-05 03:41:53]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/hbono@chromium.org/10907045/13001

[commit-bot: I haz the power, 2012-09-05 06:06:07]

Change committed as 154900