Extracts CT DNS test utilities into a standalone class

components/certificate_transparency/BUILD.gn

 # Copyright 2015 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("certificate_transparency") {
   sources = [
     "ct_policy_manager.cc",
     "ct_policy_manager.h",
     "log_dns_client.cc",
     "log_dns_client.h",
@@ skipping 12 matching lines @@
     "//components/base32",
     "//components/prefs",
     "//components/safe_json",
     "//components/url_formatter",
     "//components/url_matcher",
     "//net",
     "//url",
   ]
 }
 
+source_set("test_support") {

[Eran Messeri, 2016/07/21 14:47:02]

I suggest adding the mock_log_dns_traffic files to the unit_tests source_set and
not introducing another build rule until something outside of
components/certificate_transparency needs it.

[Rob Percival, 2016/07/21 15:27:19]

Done.

+  testonly = true
+  sources = [
+    "mock_log_dns_traffic.cc",
+    "mock_log_dns_traffic.h",
+  ]
+  public_deps = [
+    ":certificate_transparency",
+  ]
+  deps = [
+    "//base",
+    "//net",
+    "//net:test_support",
+    "//testing/gtest",
+  ]
+}
+
 source_set("unit_tests") {
   testonly = true
   sources = [
     "ct_policy_manager_unittest.cc",
     "log_dns_client_unittest.cc",
     "log_proof_fetcher_unittest.cc",
     "single_tree_tracker_unittest.cc",
   ]
-
   deps = [
-    ":certificate_transparency",
+    ":test_support",
     "//base/test:test_support",
     "//components/prefs:test_support",
     "//components/safe_json:test_support",
     "//net:test_support",
     "//testing/gmock",
     "//testing/gtest",
   ]
 }