Generate symbols in debug GN builds.

build/config/BUILDCONFIG.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.
 
 # =============================================================================
 # BUILD FLAGS
 # =============================================================================
 #
 # This block lists input arguments to the build, along with their default
 # values. GN requires listing them explicitly so it can validate input and have
@@ skipping 342 matching lines @@
 if (is_debug) {
   _native_compiler_configs += [ "//build/config:debug" ]
   _default_optimization_config = "//build/config/compiler:no_optimize"
 } else {
   _native_compiler_configs += [ "//build/config:release" ]
   _default_optimization_config = "//build/config/compiler:optimize"
 }
 _native_compiler_configs += [ _default_optimization_config ]
 
 # Symbol setup.
-if (is_clang && (is_linux || is_android)) {
-  # Clang creates chubby debug information, which makes linking very slow.
-  # For now, don't create debug information with clang.
-  # See http://crbug.com/70000
-  # TODO(brettw) This just copies GYP. Why not do this on Mac as well?
-  _default_symbols_config = "//build/config/compiler:no_symbols"
-} else if (symbol_level == 2) {
+if (symbol_level == 2) {
   _default_symbols_config = "//build/config/compiler:symbols"
 } else if (symbol_level == 1) {
   _default_symbols_config = "//build/config/compiler:minimal_symbols"
 } else if (symbol_level == 0) {
   _default_symbols_config = "//build/config/compiler:no_symbols"
 } else {
   assert(false, "Bad value for symbol_level.")
 }
 _native_compiler_configs += [ _default_symbols_config ]
 
@@ skipping 89 matching lines @@
     host_toolchain = "//build/toolchain/linux:$build_cpu_arch"
     set_default_toolchain("//build/toolchain/linux:$cpu_arch")
   }
 } else if (is_mac) {
   host_toolchain = "//build/toolchain/mac:clang"
   set_default_toolchain(host_toolchain)
 } else if (is_ios) {
   host_toolchain = "//build/toolchain/mac:host_clang"
   set_default_toolchain("//build/toolchain/mac:clang")
 }