Revert 176087

Revert 176087

Appears to break ChromeOS browser_tests.

> Re-introduce the partial magnifier
> 
> Major Changes:
> - Adding a selectbox at the right of screen magnifier setting on the setting page.
> - Adding 'screen_magnifier_type2' pref.
> - Separating the enable/disable state of magnifier from MagnifierType. MagnifierType does no longer indicate the current enable/disable status.
> - Add IsMagnifierEnabled() to shell delegate.
> 
> BUG=166832
> TEST=confirm that magnifier can be enabled/disabled via the tray and the settings page. browser_test passes.
> 
> R=zork@chromium.org, derat@chromium.org, nkostylev@chromium.org
> TBR=jhawkins@chromium.org
> # TBRing for small changed in C/B/ui/webui/options/ and C/B/resources/options/
> 
> Review URL: https://chromiumcodereview.appspot.com/11642014

TBR=yoshiki@chromium.org
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=176102