Move WeakPtrFactory members to the end in some android code

Move WeakPtrFactory members to the end in some android code

This forces WeakPtrs to be invalidated before other members' destructors run.
See the bug or the documentation of WeakPtrFactory for more information. I'm
in the process of trying to turn on a clang check for this (see the bug).

BUG=303818
TBR=yfriedman@chromium.org,boliu@chromium.org,tim@chromium.org

Committed: https://crrev.com/2d1046b2ca5c18fa03cfa2f08708bbd3be98dbdb
Cr-Commit-Position: refs/heads/master@{#311716}

[dmichael (off chromium), 2015-01-15 18:42:14]

dmichael@chromium.org changed reviewers:
+ bbudge@chromium.org

[dmichael (off chromium), 2015-01-15 18:42:56]

Mind taking a quick look? This should be the last bunch of WeakPtrFactory
mistakes I need to fix before turning on the check.

[boliu, 2015-01-15 18:48:48]

boliu@chromium.org changed reviewers:
+ boliu@chromium.org

[boliu, 2015-01-15 18:48:48]

android_webview lgtm

[bbudge, 2015-01-15 19:07:13]

lgtm

[dmichael (off chromium), 2015-01-15 19:07:43]

The CQ bit was checked by dmichael@chromium.org

[commit-bot: I haz the power, 2015-01-15 19:09:08]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/805903005/1

[commit-bot: I haz the power, 2015-01-15 19:52:20]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-01-15 19:54:30]

Patchset 1 (id:??) landed as
https://crrev.com/2d1046b2ca5c18fa03cfa2f08708bbd3be98dbdb
Cr-Commit-Position: refs/heads/master@{#311716}