Extract some account chooser views things for cross-platform use.

Extract some account chooser views things for cross-platform use.

- AvatarFetcher moves out as AccountAvatarFetcher
- Avatar icon size constant moves out as kAvatarImageSize
- Avatar icon scaling moves out as ScaleImageForAccountAvatar

BUG=448011
Committed: https://crrev.com/bcfc1b3cc8e59d4be12a4317ec95fbc97460a00c
Cr-Commit-Position: refs/heads/master@{#315316}

[dconnelly, 2015-02-06 09:25:10]

Patchset #2 (id:20001) has been deleted

[dconnelly, 2015-02-06 09:25:14]

Patchset #1 (id:1) has been deleted

[dconnelly, 2015-02-06 09:25:26]

dconnelly@chromium.org changed reviewers:
+ vasilii@chromium.org

[dconnelly, 2015-02-06 16:15:03]

dconnelly@chromium.org changed reviewers:
+ mkwst@chromium.org

[Mike West, 2015-02-06 17:06:17]

LGTM.

[vasilii, 2015-02-06 17:15:42]

lgtm

[dconnelly, 2015-02-09 14:53:02]

The CQ bit was checked by dconnelly@chromium.org

[dconnelly, 2015-02-09 14:53:11]

On 2015/02/06 17:15:42, vasilii wrote:
> lgtm

You guys are awesome reviewers.

[dconnelly, 2015-02-09 14:53:35]

On 2015/02/09 14:53:11, dconnelly wrote:
> On 2015/02/06 17:15:42, vasilii wrote:
> > lgtm
> 
> You guys are awesome reviewers.

No sarcasm btw. I think I'm required to specify that now :)

[commit-bot: I haz the power, 2015-02-09 14:53:36]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/901493003/40001

[commit-bot: I haz the power, 2015-02-09 16:13:17]

Committed patchset #1 (id:40001)

[commit-bot: I haz the power, 2015-02-09 16:13:42]

Patchset 1 (id:??) landed as
https://crrev.com/bcfc1b3cc8e59d4be12a4317ec95fbc97460a00c
Cr-Commit-Position: refs/heads/master@{#315316}