Revert 251327 "Reland of: Split out InputMethodMenuManager from ..."

> Reland of: Split out InputMethodMenuManager from InputMethodManager.
> 
> Rename input_method_property to input_method_menu_item, and move to ash/ime.
> 
> This is a reland of https://codereview.chromium.org/150203015,reverted by https://codereview.chromium.org/165453002
> 
> Use Singleton<> instead of trying to maintain my own singleton.
> 
> BUG=342336, 343044
> 
> Review URL: https://codereview.chromium.org/165783002

TBR=uekawa@chromium.org

Review URL: https://codereview.chromium.org/167823002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@251436 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 251436