ui: Move screen unit test into gfx_unittests target.

ui/gfx/gfx_tests.gyp

Index: ui/gfx/gfx_tests.gyp
diff --git a/ui/gfx/gfx_tests.gyp b/ui/gfx/gfx_tests.gyp
index 174e2bf8da7a4e3bf29f5f209f4e9294af086421..59e14d384766d33d9b3d1b1c113f4b082b65fe8c 100644
--- a/ui/gfx/gfx_tests.gyp
+++ b/ui/gfx/gfx_tests.gyp
@@ -21,6 +21,7 @@
         'image/image_unittest_util.h',
         'image/image_unittest_util_ios.mm',
         'image/image_unittest_util_mac.mm',
+        'screen_unittest.cc',
         'test/run_all_unittests.cc',
         'text_elider_unittest.cc',
         'text_utils_unittest.cc',
@@ -137,6 +138,11 @@
             'render_text_unittest.cc',
           ],
         }],
+        ['use_aura==1', {
+          'sources!': [
+            'screen_unittest.cc',
+          ],
+        }],
       ],
     }
   ],