Make goma work on win GN builds.

build/config/BUILDCONFIG.gn

Index: build/config/BUILDCONFIG.gn
diff --git a/build/config/BUILDCONFIG.gn b/build/config/BUILDCONFIG.gn
index 0d65c44da6405e085e737fc6ad50a1f47a13fdbb..957953df40ebfe25fda7afdc3363ca0669b95357 100644
--- a/build/config/BUILDCONFIG.gn
+++ b/build/config/BUILDCONFIG.gn
@@ -373,7 +373,9 @@ if (symbol_level == -1) {
 }
 
 # Symbol setup.
-if (symbol_level == 2) {
+if (is_win && use_goma) {
+  _default_symbols_config = "//build/config/compiler:no_symbols"

[scottmg, 2014/11/20 04:58:34]

this should be minimal_symbols not no_symbols, otherwise there will be no
stacktraces when there's a crash on a bot.

it shouldn't really be based on use_goma either i don't think, i think some
bots/people use_goma with win_z7 (which replaces /Zi with /Z7) to get symbols on
goma win builds.

but if you want to do this temporarily, it's ok as minimal_symbols.

[Dirk Pranke, 2014/11/20 05:01:03]

Okay, I will look into this more tomorrow.

+} else if (symbol_level == 2) {

[Dirk Pranke, 2014/11/20 03:47:13]

I'm not sure if this is a great place for a win-goma-specific block, but putting
things inside the configs in compiler/BUILD.gn seemed even worse.

   _default_symbols_config = "//build/config/compiler:symbols"
 } else if (symbol_level == 1) {
   _default_symbols_config = "//build/config/compiler:minimal_symbols"