Revert of Use last active profile instead of default profile in profile manager

Revert of Use last active profile instead of default profile in profile manager (patchset #2 id:40001 of https://codereview.chromium.org/1051843002/)

Reason for revert:
This CL breaks guest mode in Windows 8 metro mode crbug.com/480400. Reverting it to find a suitable fix that solves both 450192 and 480400.

Original issue's description:
> Use last active profile instead of default profile in profile manager
>
> When profiles are deleted, new profiles are created in the directory
> Profile X. These directories are stored in last active profile. In metro
> mode, on initialization rather than last active profile, default profile
> corresponding to the directory Default is used resulting in problems
> on profile deletion. This CL makes ProfileManager::GetActiveUserProfile
> return last active profile instead of default profile for windows build
> to solve the problem.
>
> BUG=450192
>
> Committed: https://crrev.com/e4bc3e8aae7ab612458ba94b0c6065dab7ae1da9
> Cr-Commit-Position: refs/heads/master@{#325440}

TBR=skuhne@chromium.org,dpolukhin@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=450192
Committed: https://crrev.com/651f3588630e17584eccd4dc4507011e9bd6dfeb
Cr-Commit-Position: refs/heads/master@{#328122}

[kaliamoorthi, 2015-05-04 14:32:06]

Created Revert of Use last active profile instead of default profile in profile
manager

[commit-bot: I haz the power, 2015-05-04 14:32:31]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1113333005/1

[commit-bot: I haz the power, 2015-05-04 14:33:02]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-05-04 14:34:04]

Patchset 1 (id:??) landed as
https://crrev.com/651f3588630e17584eccd4dc4507011e9bd6dfeb
Cr-Commit-Position: refs/heads/master@{#328122}