Remove implicit conversions from scoped_refptr to T* in extensions/

Remove implicit conversions from scoped_refptr to T* in extensions/

This patch was generated by running the rewrite_scoped_refptr clang tool
on a Linux build.

BUG=110610
Committed: https://crrev.com/7921e3faac8556ad9e24c533b8019f85b99e6911
Cr-Commit-Position: refs/heads/master@{#291770}

[not at google - send to devlin, 2014-08-25 20:35:40]

lgtm

[dcheng, 2014-08-25 21:07:44]

The CQ bit was checked by dcheng@chromium.org

[commit-bot: I haz the power, 2014-08-25 21:09:37]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/dcheng@chromium.org/503873002/1

[commit-bot: I haz the power, 2014-08-25 21:44:36]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  linux_chromium_rel_swarming on tryserver.chromium.linux
(http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

[commit-bot: I haz the power, 2014-08-25 22:20:26]

Committed patchset #1 (1) as 313125c73cf46fb78b384adb6e57e782f358aaaf

[commit-bot: I haz the power, 2014-09-10 02:37:54]

Patchset 1 (id:??) landed as
https://crrev.com/7921e3faac8556ad9e24c533b8019f85b99e6911
Cr-Commit-Position: refs/heads/master@{#291770}