Introduce the WebState iOS provider interface.

ios/ios_base.gyp

Index: ios/ios_base.gyp
diff --git a/ios/ios_consumer.gyp b/ios/ios_base.gyp
similarity index 58%
copy from ios/ios_consumer.gyp
copy to ios/ios_base.gyp
index f83a0eb3ad828987ff9def682de8d43f987f572d..f15192a8618d7a94598160b60dd3a833b5e0eb24 100644
--- a/ios/ios_consumer.gyp
+++ b/ios/ios_base.gyp
@@ -22,20 +22,5 @@
         'public/consumer/base/util.h',
       ],
     },
-    {
-      'target_name': 'ios_consumer_unittests',
-      'type': '<(gtest_target_type)',
-      'dependencies': [
-        '../base/base.gyp:base',
-        '../base/base.gyp:run_all_unittests',
-        '../base/base.gyp:test_support_base',
-        '../testing/gmock.gyp:gmock',
-        '../testing/gtest.gyp:gtest',
-        'ios_consumer_base',
-      ],
-      'sources': [
-        'consumer/base/supports_user_data_unittest.cc',
-      ],
-    },
   ],
 }