build: Remove build system support for gold plugin, except under ChromeOS.

build/config/compiler/compiler.gni

 # Copyright 2015 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/android/config.gni")
 import("//build/config/arm.gni")
 import("//build/config/chrome_build.gni")
 import("//build/config/chromecast_build.gni")
 import("//build/config/compiler/pgo/pgo.gni")
 import("//build/config/sanitizers/sanitizers.gni")
@@ skipping 102 matching lines @@
   # Whether or not the official builds should be built with full WPO. Enabled by
   # default for the PGO and the x64 builds.
   if (chrome_pgo_phase > 0) {
     full_wpo_on_official = true
   } else {
     full_wpo_on_official = false
   }
 }
 
 declare_args() {
+  # Set to true to use lld, the LLVM linker. This flag may be used on Windows,
+  # Linux or Fuchsia.
+  use_lld = (is_win && host_os != "win") || is_fuchsia ||
+            ((allow_posix_link_time_opt || is_cfi) && target_os == "linux" &&
+             !is_chromeos && target_cpu == "x64")
+}
+
+declare_args() {
   # Whether to use the gold linker from binutils instead of lld or bfd.
   use_gold =
       (!use_lld && !(is_chromecast && is_linux &&
                      (current_cpu == "arm" || current_cpu == "mipsel")) &&
        (is_linux && (current_cpu == "x64" || current_cpu == "x86" ||
                      current_cpu == "arm" || current_cpu == "mipsel"))) ||
       (is_android && (current_cpu == "x86" || current_cpu == "x64" ||
                       current_cpu == "arm" || current_cpu == "arm64"))
 }
 
@@ skipping 39 matching lines @@
 }
 
 # Assert that the configuration isn't going to hit https://crbug.com/648948.
 assert(ignore_elf32_limitations || !is_android ||
            (android_64bit_target_cpu && !build_apk_secondary_abi) ||
            is_component_build || symbol_level < 2,
        "Android 32-bit non-component builds cannot have symbol_level=2 " +
            "due to 4GiB file size limit, see https://crbug.com/648948. " +
            "If you really want to try this out, " +
            "set ignore_elf32_limitations=true.")