Revert 256507 "Exclude unused strings for chrome://ntp on Android"

Breaks ExtensionApiTest.CookiesEventsSpanning

> Exclude unused strings for chrome://ntp on Android
> 
> Relanding https://codereview.chromium.org/174453002 as it got reverted in https://codereview.chromium.org/177903009
> 
> BUG=326023
> TBR=estade
> 
> Review URL: https://codereview.chromium.org/183793008

TBR=aurimas@chromium.org

Review URL: https://codereview.chromium.org/196423006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@256523 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 256523