Add chrome perf tests and sniffer to GN build.

chrome/test/BUILD.gn

 # Copyright 2014 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.
 
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 
+# This target exists to reference other test executables to bring these files
+# into the build.
+group("test") {
+  testonly = true
+  deps = [
+    "//chrome/test/perf",
+  ]
+}
+
 # GYP version: chrome/chrome_tests_unit.gypi:test_support_common
 source_set("test_support") {
   defines = []
   testonly = true
 
   sources = [
     "base/chrome_process_util.cc",
     "base/chrome_process_util.h",
     "base/chrome_process_util_mac.cc",
     "base/chrome_render_view_host_test_harness.cc",
@@ skipping 177 matching lines @@
     ":test_support",
     "//base",
     "//chrome:resources",
     "//chrome:strings",
     "//chrome/browser",
     "//chrome/common",
     "//mojo/edk/system",
     "//mojo/environment:chromium",
   ]
 }