Make Pepper WebSocket UtilityGetProtocol test less flaky by making the wsh wait for close

Make Pepper WebSocket UtilityGetProtocol test less flaky by making the wsh wait for close

Attempt to fix the flakiness by making sure the server handler doesn't exit
before the client closes.

BUG=389084
R=jgraettinger,yhirano

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=285500

[yhirano, 2014-07-24 05:40:17]

lgtm

[tyoshino (SeeGerritForStatus), 2014-07-24 05:42:49]

+jgraettinger

[Johnny, 2014-07-24 14:34:56]

lgtm

[tyoshino (SeeGerritForStatus), 2014-07-25 03:28:59]

The CQ bit was checked by tyoshino@chromium.org

[commit-bot: I haz the power, 2014-07-25 03:30:47]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/tyoshino@chromium.org/410383003/1

[tyoshino (SeeGerritForStatus), 2014-07-25 03:31:53]

The CQ bit was unchecked by tyoshino@chromium.org

[tyoshino (SeeGerritForStatus), 2014-07-25 03:32:05]

The CQ bit was checked by tyoshino@chromium.org

[commit-bot: I haz the power, 2014-07-25 03:33:12]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/tyoshino@chromium.org/410383003/1

[commit-bot: I haz the power, 2014-07-25 06:05:33]

Change committed as 285500