Add more components tests to GN build.

components/web_cache/common/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.
 
-static_library("common") {
-  output_name = "web_cache_common"
+source_set("common") {
   sources = [
     "web_cache_message_generator.cc",
     "web_cache_message_generator.h",
     "web_cache_messages.h",
   ]
 
   deps = [
     "//ipc",
   ]
 }