Fix gaia logout URLFetcher memory leak

Fix gaia logout URLFetcher memory leak

Store the gaia logout url request so the URLFetcher object isn't leaked.

BUG=482459
TEST=google_api_unittests

Committed: https://crrev.com/1162a2e5e6439ff065910fec67f7919034841b9c
Cr-Commit-Position: refs/heads/master@{#327500}

[dtapuska, 2015-04-29 14:24:42]

dtapuska@chromium.org changed reviewers:
+ mlerman@chromium.org, rogerta@chromium.org

[Mike Lerman, 2015-04-29 14:41:37]

Thanks for sending out a patch to fix this :)

(non-owner) lgtm

[Roger Tawa OOO till Jul 10th, 2015-04-29 15:13:56]

lgtm

[dtapuska, 2015-04-29 15:23:33]

The CQ bit was checked by dtapuska@chromium.org

[commit-bot: I haz the power, 2015-04-29 15:23:42]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1108053003/1

[commit-bot: I haz the power, 2015-04-29 16:03:47]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-04-29 16:04:37]

Patchset 1 (id:??) landed as
https://crrev.com/1162a2e5e6439ff065910fec67f7919034841b9c
Cr-Commit-Position: refs/heads/master@{#327500}