Have the ui_test_support target be of type none on iOS.

ui/ui_unittests.gypi

 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 {
   'targets': [
     {
       'target_name': 'ui_test_support',
-      'type': 'static_library',
       'dependencies': [
         '../base/base.gyp:base',
         '../skia/skia.gyp:skia',
         '../testing/gtest.gyp:gtest',
       ],
       'sources': [
         'base/test/cocoa_test_event_utils.h',
         'base/test/cocoa_test_event_utils.mm',
         'base/test/ui_cocoa_test_helper.h',
         'base/test/ui_cocoa_test_helper.mm',
         'base/test/ui_controls.h',
         'base/test/ui_controls_aura.cc',
         'base/test/ui_controls_gtk.cc',
         'base/test/ui_controls_internal_win.cc',
         'base/test/ui_controls_internal_win.h',
         'base/test/ui_controls_mac.mm',
         'base/test/ui_controls_win.cc',
       ],
       'include_dirs': [
         '../',
       ],
       'conditions': [
         ['OS!="ios"', {
+          'type': 'static_library',
           'includes': [ 'base/ime/ime_test_support.gypi' ],
         }, {  # OS=="ios"
+          # None of the sources in this target are built on iOS, resulting in
+          # link errors when building targets that depend on this target
+          # because the static library isn't found. If this target is changed
+          # to have sources that are built on iOS, the target should be changed
+          # to be of type static_library on all platforms.
+          'type': 'none',
           # The cocoa files don't apply to iOS.
           'sources/': [['exclude', 'cocoa']],
         }],
         ['chromeos==1', {
           'dependencies': [
             '../chromeos/chromeos.gyp:chromeos_test_support_without_gmock',
             '../skia/skia.gyp:skia',
           ],
         }],
         ['use_aura==1', {
@@ skipping 288 matching lines @@
           'variables': {
             'test_suite_name': 'ui_unittests',
             'input_shlib_path': '<(SHARED_LIB_DIR)/<(SHARED_LIB_PREFIX)ui_unittests<(SHARED_LIB_SUFFIX)',
           },
           'includes': [ '../build/apk_test.gypi' ],
         },
       ],
     }],
   ],
 }