Convert some GN test support targets to static libs.

crypto/BUILD.gn

 # Copyright (c) 2013 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/crypto.gni")
 import("//testing/test.gni")
 
 component("crypto") {
   output_name = "crcrypto"  # Avoid colliding with OpenSSL's libcrypto.
   sources = [
@@ skipping 157 matching lines @@
     ":platform",
     ":test_support",
     "//base",
     "//base/test:run_all_unittests",
     "//base/test:test_support",
     "//testing/gmock",
     "//testing/gtest",
   ]
 }
 
+# This has no sources in some cases so can't be a static library.
 source_set("test_support") {
-  sources = [
-    "scoped_test_nss_chromeos_user.cc",
-    "scoped_test_nss_chromeos_user.h",
-    "scoped_test_nss_db.cc",
-    "scoped_test_nss_db.h",
-    "scoped_test_system_nss_key_slot.cc",
-    "scoped_test_system_nss_key_slot.h",
-  ]
-  deps = [
-    ":crypto",
-    ":platform",
-    "//base",
-  ]
+  testonly = true
+  sources = []
 
-  if (!use_nss_certs) {
-    sources -= [
+  if (use_nss_certs) {
+    sources += [
       "scoped_test_nss_db.cc",
       "scoped_test_nss_db.h",
     ]
   }
 
-  if (!is_chromeos) {
-    sources -= [
+  if (is_chromeos) {
+    sources += [
       "scoped_test_nss_chromeos_user.cc",
       "scoped_test_nss_chromeos_user.h",
       "scoped_test_system_nss_key_slot.cc",
       "scoped_test_system_nss_key_slot.h",
     ]
   }
+
+  deps = [
+    ":crypto",
+    ":platform",
+    "//base",
+  ]
 }
 
 config("platform_config") {
   if (use_nss_certs && is_clang) {
     # There is a broken header guard in /usr/include/nss/secmod.h:
     # https://bugzilla.mozilla.org/show_bug.cgi?id=884072
     cflags = [ "-Wno-header-guard" ]
   }
 }
 
 # This is a meta-target that forwards to NSS's SSL library or OpenSSL,
 # according to the state of the crypto flags. A target just wanting to depend
 # on the current SSL library should just depend on this.
 group("platform") {
   public_deps = [
     "//third_party/boringssl",
   ]
 
   # Link in NSS if it is used for the platform certificate library
   # (use_nss_certs).
   if (use_nss_certs) {
     public_configs = [ ":platform_config" ]
     public_configs += [ "//third_party/nss:system_nss_no_ssl_config" ]
   }
 }