Convert GN single-item list concat to use lists.

base/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.
 
 component("base") {
   external = true
   sources = [
     "../build/build_config.h",
     "third_party/dmg_fp/dmg_fp.h",
     "third_party/dmg_fp/g_fmt.cc",
@@ skipping 656 matching lines @@
     "win/text_services_message_filter.h",
     "win/win_util.cc",
     "win/win_util.h",
     "win/windows_version.cc",
     "win/windows_version.h",
     "win/wrapped_window_proc.cc",
     "win/wrapped_window_proc.h",
   ]
 
   # TODO(brettw) I don't understand the conditions this file is used.
-  sources -= "files/file_path_watcher_stub.cc"
+  sources -= [ "files/file_path_watcher_stub.cc" ]
 
   sources -= [
     # TODO(brettw) do these properly.
     "message_loop/message_pump_aurax11.cc",
     "message_loop/message_pump_aurax11.h",
     "message_loop/message_pump_ozone.cc",
     "message_loop/message_pump_ozone.h",
 
     "process/process_handle_freebsd.cc",
     "process/process_handle_openbsd.cc",
@@ skipping 57 matching lines @@
   if (is_win) {
     sources -= [
       "message_loop/message_pump_libevent.cc",
       "strings/string16.cc",
       # Not using sha1_win.cc because it may have caused a
       # regression to page cycler moz.
       "sha1_win.cc",
     ]
 
     if (is_component_build) {
-      sources -= "debug/debug_on_start_win.cc"
+      sources -= [ "debug/debug_on_start_win.cc" ]
     }
   } else if (!is_nacl) {
     # Non-Windows.
-    deps += "//third_party/libevent"
-    libs += "dl"
+    deps += [ "//third_party/libevent" ]
+    libs += [ "dl" ]
   }
 
   # Mac.
   if (is_mac) {
     sources -= [
       "base_paths_posix.cc",
       "native_library_posix.cc",
       "strings/sys_string_conversions_posix.cc",
     ]
-    deps += "//third_party/mach_override"
+    deps += [ "//third_party/mach_override" ]
     libs += [
       "AppKit.framework",
       "ApplicationServices.framework",
       "Carbon.framework",
       "CoreFoundation.framework",
       "Foundation.framework",
       "IOKit.framework",
       "Security.framework",
     ]
   } else {
     # Non-Mac.
-    sources -= "files/file_path_watcher_kqueue.cc"
+    sources -= [ "files/file_path_watcher_kqueue.cc" ]
   }
 
   # IOS.
   if (is_ios) {
     libs += [
       "CoreFoundation.framework",
       "CoreGraphics.framework",
       "CoreText.framework",
       "Foundation.framework",
       "UIKit.framework",
@@ skipping 83 matching lines @@
   configs += [ "//build/config/compiler:wexit_time_destructors" ]
   deps = [
     ":base",
     "//base/third_party/dynamic_annotations",
     "//third_party/icu:icui18n",
     "//third_party/icu:icuuc",
   ]
 
   if (toolkit_uses_gtk) {
     # i18n/rtl.cc uses gtk
-    configs += "//build/config/linux:gtk"
+    configs += [ "//build/config/linux:gtk" ]
   }
 
   #'conditions': [
   #  ['OS == "win"', {
   #    # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
   #    'msvs_disabled_warnings': [
   #      4267,
   #    ],
   #  }],
   #],
   #'variables': {
   #  'optimize': 'max',
   #},
 }