Moving the initialization of AtExitManager to base::android::Init()

Moving the initialization of AtExitManager to
base::android::Init(), it shouldn't be part of JNI
registration, So the embedded which doesn't require
to register JNI methods (like WebView) could still
work properly.

BUG=464008
Committed: https://crrev.com/f40324b8e160c353366b03492051f0a8eae90dcb
Cr-Commit-Position: refs/heads/master@{#320166}

[michaelbai, 2015-03-11 20:24:38]

michaelbai@chromium.org changed reviewers:
+ nyquist@chromium.org

[nyquist, 2015-03-11 20:27:37]

lgtm, but could you split up the CL description? It's a very long line. I think
it would make sense to have a short paragraph explaining why this is done and
how it should be used on the different platforms (webview/chrome).

[michaelbai, 2015-03-11 20:43:24]

done, in cq

[michaelbai, 2015-03-11 20:43:26]

The CQ bit was checked by michaelbai@chromium.org

[commit-bot: I haz the power, 2015-03-11 20:44:30]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/995313003/1

[commit-bot: I haz the power, 2015-03-11 22:20:44]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-03-11 22:21:43]

Patchset 1 (id:??) landed as
https://crrev.com/f40324b8e160c353366b03492051f0a8eae90dcb
Cr-Commit-Position: refs/heads/master@{#320166}