Add metrics for quantity and type of Favicon candidates

components/favicon/content/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.
 
 static_library("content") {
   sources = [
     "content_favicon_driver.cc",
     "content_favicon_driver.h",
     "favicon_url_util.cc",
     "favicon_url_util.h",
@@ skipping 13 matching lines @@
   ]
 }
 
 source_set("unit_tests") {
   testonly = true
   sources = [
     "content_favicon_driver_unittest.cc",
   ]
   deps = [
     ":content",
+    "//base/test:test_support",
     "//components/favicon/core",
     "//content/public/browser",
     "//content/public/common",
     "//content/test:test_support",
     "//skia",
+    "//testing/gmock",
     "//testing/gtest",
   ]
 }