MacViews: Fix builds when use_aura XOR toolkit_views is TRUE.

Ozone has use_aura=1 and toolkit_views=0. MacViews has use_aura=0 and
toolkit_views=1. Ensure these both link correctly.

This is a follow-up to r266641 and r266283.

BUG=366007
TBR=ben@chromium.org

Review URL: https://codereview.chromium.org/252963004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@266965 0039d316-1c4b-4281-b951-d872f2087c98

ui/gfx/gfx.gyp

@@ -348,7 +348,7 @@
             ],
           },
         }],
-        ['use_aura==0', {
+        ['use_aura==0 and toolkit_views==0', {
           'sources!': [
             'nine_image_painter.cc',
             'nine_image_painter.h',