Split FaviconService and FaviconServiceImpl.

components/favicon/core/test/BUILD.gn

Index: components/favicon/core/test/BUILD.gn
diff --git a/components/favicon/core/test/BUILD.gn b/components/favicon/core/test/BUILD.gn
new file mode 100644
index 0000000000000000000000000000000000000000..d87927d2d851e8388e62f92cd6433659ac226b5d
--- /dev/null
+++ b/components/favicon/core/test/BUILD.gn
@@ -0,0 +1,19 @@
+# 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.
+
+static_library("test_support") {
+  testonly = true
+
+  sources = [
+    "mock_favicon_service.cc",
+    "mock_favicon_service.h",
+  ]
+
+  public_deps = [
+    "//base",
+    "//components/favicon/core",
+    "//components/favicon_base",
+    "//testing/gmock",
+  ]
+}