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

build/config/compiler/compiler.gni

Index: build/config/compiler/compiler.gni
diff --git a/build/config/compiler/compiler.gni b/build/config/compiler/compiler.gni
index 83369d944c8850513bb5b405711df779ccb0d499..73f3bf04e61c47a856a070d03479125e7508a212 100644
--- a/build/config/compiler/compiler.gni
+++ b/build/config/compiler/compiler.gni
@@ -119,6 +119,14 @@ declare_args() {
   }
 }
 
+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 =