Fix memory leak in HidServiceTest.Create from r285774

Fix memory leak in HidServiceTest.Create from r285774

To fix tree-closer in Linux ASan LSan Tests (1) since
http://build.chromium.org/p/chromium.memory/builders/Linux%20ASan%20LSan%20Tests%20%281%29/builds/4338

errors like

Direct leak of 72 byte(s) in 1 object(s) allocated from:
    #0 0x44145b in operator new(unsigned long) /usr/local/google/work/chromium/src/third_party/llvm/projects/compiler-rt/lib/asan/asan_new_delete.cc:55
    #1 0x5e8afd in device::HidService::Create(scoped_refptr\u003Cbase::MessageLoopProxy>) device/hid/hid_service.cc:26
    #2 0x509324 in device::HidServiceTest_Create_Test::TestBody() device/hid/hid_service_unittest.cc:15

BUG=367145
NOTRY=true
NOTREECHECKS=true
TBR=rockot@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=285848

[tapted, 2014-07-28 00:03:04]

The CQ bit was checked by tapted@chromium.org

[commit-bot: I haz the power, 2014-07-28 00:03:28]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/tapted@chromium.org/424623002/1

[tapted, 2014-07-28 00:22:34]

The CQ bit was unchecked by tapted@chromium.org

[tapted, 2014-07-28 00:22:35]

The CQ bit was checked by tapted@chromium.org

[commit-bot: I haz the power, 2014-07-28 00:23:00]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/tapted@chromium.org/424623002/1

[commit-bot: I haz the power, 2014-07-28 00:24:46]

Change committed as 285848

[Reilly Grant (use Gerrit), 2014-07-28 01:11:42]

lgtm (I'll be an owner of this code someday.)

[Ken Rockot(use gerrit already), 2014-07-28 12:20:22]

Doh. Thanks for fixing this.