Convert third_party source sets to static libraries.

third_party/ced/BUILD.gn

 # Copyright 2016 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("//testing/test.gni")
 
 config("ced_config") {
   include_dirs = [ "src" ]
   if (is_clang) {
     cflags = [ "-Wno-unused-function" ]
   }
 }
 
-source_set("ced") {
+static_library("ced") {
   sources = [
     "src/compact_enc_det/compact_enc_det.cc",
     "src/compact_enc_det/compact_enc_det.h",
     "src/compact_enc_det/compact_enc_det_generated_tables.h",
     "src/compact_enc_det/compact_enc_det_generated_tables2.h",
     "src/compact_enc_det/compact_enc_det_hint_code.cc",
     "src/compact_enc_det/compact_enc_det_hint_code.h",
     "src/util/basictypes.h",
     "src/util/build_config.h",
     "src/util/commandlineflags.h",
@@ skipping 43 matching lines @@
   } else {
     defines = [ "COMPILER_GCC" ]
   }
 
   deps = [
     ":ced",
     "//testing/gtest",
     "//testing/gtest:gtest_main",
   ]
 }