Revert of ui:: Add --ui-enable-map-image flag. (https://codereview.chromium.org/199403002/)

Reason for revert:
Attempting to see if this fixes a ChromeOS test that has been failing consistently on the ASAN bot since this change was introduced. Will revert the revert if it doesn't fix it.

http://build.chromium.org/p/chromium.memory/builders/Linux%20Chromium%20OS%20ASan%2BLSan%20Tests%20%281%29/builds/263

Original issue's description:
> ui:: Add --ui-enable-map-image flag.
> 
> BUG=350737
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=257020

TBR=danakj@chromium.org,fjhenigman@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=350737

Review URL: https://codereview.chromium.org/198233004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@257060 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 257060