Remove implicit conversions from scoped_refptr to T* in content/

Remove implicit conversions from scoped_refptr to T* in content/

Manual fixups for cases the automated tooling elected to skip.

BUG=110610
Committed: https://crrev.com/4b8efd09c667171b4911bdf19aab3714cd62c37a
Cr-Commit-Position: refs/heads/master@{#298745}

[dcheng, 2014-10-07 22:17:44]

dcheng@chromium.org changed reviewers:
+ qinmin@chromium.org, sievers@chromium.org, torne@chromium.org

[dcheng, 2014-10-07 22:17:44]

+torne for content/browser/android/java/ changes
+sievers for content/browser/renderer_host changes
+qinmin for content/renderer/media changes

[no sievers, 2014-10-07 22:20:48]

lgtm

[Torne, 2014-10-08 11:31:58]

lgtm

[qinmin, 2014-10-08 17:38:44]

lgtm

[dcheng, 2014-10-08 17:39:18]

The CQ bit was checked by dcheng@chromium.org

[commit-bot: I haz the power, 2014-10-08 17:39:43]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/632283004/1

[commit-bot: I haz the power, 2014-10-08 18:10:22]

Committed patchset #1 (id:1) as 2a17f36f7628ae2eec4964b42e7be939b799148b

[commit-bot: I haz the power, 2014-10-08 18:12:15]

Patchset 1 (id:??) landed as
https://crrev.com/4b8efd09c667171b4911bdf19aab3714cd62c37a
Cr-Commit-Position: refs/heads/master@{#298745}