Make goma work on win 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 355 matching lines @@
   # Linux is slowed by having symbols as part of the target binary, whereas
   # Mac and Windows have them separate, so in Release Linux, default them off.
   if (is_debug || !is_linux) {
     symbol_level = 2
   } else {
     symbol_level = 0
   }
 }
 
 # Symbol setup.
+import("//build/toolchain/goma.gni")

[brettw, 2014/11/21 05:28:03]

This will make all goma variables global. I'd like to discuss other ways to do
this. Will be busty Friday, maybe we can discuss Monday.

[Dirk Pranke, 2014/11/21 17:00:57]

ok.

 if (symbol_level == 2) {
-  _default_symbols_config = "//build/config/compiler:symbols"
+  if (is_win && use_goma) {
+    # GOMA doesn't support full symbols on Win.

[scottmg, 2014/11/21 02:35:41]

Make this TODO(): we don't handle /Z7 yet, so avoid PDB for now.

[Dirk Pranke, 2014/11/21 02:46:00]

Will do.

+    _default_symbols_config = "//build/config/compiler:minimal_symbols"
+  } else {
+    _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 ]
 
 # Windows linker setup for EXEs and DLLs.
@@ skipping 304 matching lines @@
       if (defined(invoker.output_extension)) { output_extension = invoker.output_extension }
       if (defined(invoker.output_name)) { output_name = invoker.output_name }
       if (defined(invoker.public)) { public = invoker.public }
       if (defined(invoker.public_configs)) { public_configs = invoker.public_configs }
       if (defined(invoker.public_deps)) { public_deps = invoker.public_deps }
       if (defined(invoker.sources)) { sources = invoker.sources }
       if (defined(invoker.visibility)) { visibility = invoker.visibility }
     }
   }
 }