Split up ios/web:test_support.

ios/web/public/test/response_providers/BUILD.gn

Index: ios/web/public/test/response_providers/BUILD.gn
diff --git a/ios/web/public/test/response_providers/BUILD.gn b/ios/web/public/test/response_providers/BUILD.gn
new file mode 100644
index 0000000000000000000000000000000000000000..3a05752725ecfea257d2ddcf30e12d5e50f1d2ef
--- /dev/null
+++ b/ios/web/public/test/response_providers/BUILD.gn
@@ -0,0 +1,38 @@
+# Copyright 2017 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.
+
+source_set("test_support") {
+  testonly = true
+
+  deps = [
+    "//base",
+    "//base/test:test_support",
+    "//ios/third_party/gcdwebserver",
+    "//net",
+    "//url",
+  ]
+
+  sources = [
+    "data_response_provider.h",
+    "data_response_provider.mm",
+    "delayed_response_provider.h",
+    "delayed_response_provider.mm",
+    "error_page_response_provider.h",
+    "error_page_response_provider.mm",
+    "file_based_response_provider.h",
+    "file_based_response_provider.mm",
+    "file_based_response_provider_impl.h",
+    "file_based_response_provider_impl.mm",
+    "html_response_provider.h",
+    "html_response_provider.mm",
+    "html_response_provider_impl.h",
+    "html_response_provider_impl.mm",
+    "http_auth_response_provider.h",
+    "http_auth_response_provider.mm",
+    "response_provider.h",
+    "response_provider.mm",
+    "string_response_provider.h",
+    "string_response_provider.mm",
+  ]
+}