Convert third_party source sets to static libraries.

third_party/protobuf/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.
 
 config("protobuf_config") {
   include_dirs = [ "src" ]
   defines = [
     "GOOGLE_PROTOBUF_NO_RTTI",
     "GOOGLE_PROTOBUF_NO_STATIC_INITIALIZER",
   ]
@@ skipping 157 matching lines @@
   # Required for component builds. See http://crbug.com/172800.
   if (is_component_build) {
     public_configs += [ ":protobuf_use_dlls" ]
     defines = [ "LIBPROTOBUF_EXPORTS" ]
   }
 }
 
 # This is the full, heavy protobuf lib that's needed for c++ .protos that don't
 # specify the LITE_RUNTIME option. The protocol compiler itself (protoc) falls
 # into that category. Do not use in Chrome code.
-source_set("protobuf_full") {
+static_library("protobuf_full") {
   # Prevent people from depending on this outside our file.
   visibility = [ ":*" ]
 
   sources = protobuf_lite_sources
   sources += [
     "src/google/protobuf/any.cc",
     "src/google/protobuf/any.h",
     "src/google/protobuf/any.pb.cc",
     "src/google/protobuf/any.pb.h",
     "src/google/protobuf/api.pb.cc",
@@ skipping 142 matching lines @@
   ]
 
   cflags = protobuf_lite_cflags
 }
 
 # Only compile the compiler for the host architecture.
 if (current_toolchain == host_toolchain) {
   # protoc compiler is separated into protoc library and executable targets to
   # support protoc plugins that need to link libprotoc, but not the main()
   # itself. See src/google/protobuf/compiler/plugin.h
-  source_set("protoc_lib") {
+  static_library("protoc_lib") {
     sources = [
       "src/google/protobuf/compiler/code_generator.cc",
       "src/google/protobuf/compiler/code_generator.h",
       "src/google/protobuf/compiler/command_line_interface.cc",
       "src/google/protobuf/compiler/command_line_interface.h",
       "src/google/protobuf/compiler/cpp/cpp_enum.cc",
       "src/google/protobuf/compiler/cpp/cpp_enum.h",
       "src/google/protobuf/compiler/cpp/cpp_enum_field.cc",
       "src/google/protobuf/compiler/cpp/cpp_enum_field.h",
       "src/google/protobuf/compiler/cpp/cpp_extension.cc",
@@ skipping 291 matching lines @@
     ":copy_google_protobuf_internal",
     ":copy_six",
   ]
 
   # Targets that depend on this should depend on the copied data files.
   data = get_target_outputs(":copy_google")
   data += get_target_outputs(":copy_six")
   data += get_target_outputs(":copy_google_protobuf")
   data += get_target_outputs(":copy_google_protobuf_internal")
 }