Fix an issue where Chrome doesn't always restart from chrome://flags.

Fix an issue where Chrome doesn't always restart from chrome://flags.

The issue is that the Android system may take a long time to call
onDestroy on the activities, which is the signal we are currently
looking for. Give it a second to clean up instead and kill it regardless
if it's still not done.

BUG=486951
Committed: https://crrev.com/18d9c28b4bdc452a9b9ff90d3873f92ab2c7b978
Cr-Commit-Position: refs/heads/master@{#332089}

[Maria, 2015-05-30 00:01:37]

mariakhomenko@chromium.org changed reviewers:
+ tedchoc@chromium.org

[Ted C, 2015-05-30 00:04:38]

lgtm

[Maria, 2015-05-30 00:05:57]

The CQ bit was checked by mariakhomenko@chromium.org

[commit-bot: I haz the power, 2015-05-30 00:06:38]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1160233002/1

[commit-bot: I haz the power, 2015-05-30 00:43:51]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-05-30 00:44:43]

Patchset 1 (id:??) landed as
https://crrev.com/18d9c28b4bdc452a9b9ff90d3873f92ab2c7b978
Cr-Commit-Position: refs/heads/master@{#332089}