Code refactor related to WeakPtrFactory in content/browser module

Changing in the intialization order of WeakPtrFactory in content/browser module
such that all member variables should appear before the WeakPtrFactory
to ensure that any WeakPtrs to Controller are invalidated before its members
variable's destructors are executed, rendering them invalid.

BUG=303818
Committed: https://crrev.com/875dc1fdfcf23ff64f959f423117fc25fd05b4e4
Cr-Commit-Position: refs/heads/master@{#298383}

[krish, 2014-09-19 08:51:44]

krish.botta@samsung.com changed reviewers:
+ l.gombos@samsung.com, mohan.reddy@samsung.com

[krish, 2014-09-26 06:26:52]

krish.botta@samsung.com changed reviewers:
+ sky@chromium.org

[krish, 2014-09-26 06:26:52]

sky@chromium.org: Please review changes in 
content/browser module

[krish, 2014-10-06 06:20:23]

On 2014/09/26 06:26:52, krish wrote:
> mailto:sky@chromium.org: Please review changes in 
> content/browser module

PTAL

[sky, 2014-10-06 14:10:00]

LGTM

[krish, 2014-10-07 03:39:33]

The CQ bit was checked by krish.botta@samsung.com

[commit-bot: I haz the power, 2014-10-07 03:42:31]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/589463002/1

[commit-bot: I haz the power, 2014-10-07 05:39:29]

Committed patchset #1 (id:1) as 1381b3937cb871989a177dd7a397a37c424daed2

[commit-bot: I haz the power, 2014-10-07 05:40:08]

Patchset 1 (id:??) landed as
https://crrev.com/875dc1fdfcf23ff64f959f423117fc25fd05b4e4
Cr-Commit-Position: refs/heads/master@{#298383}