Fix GN generation for WinASAN build

BUILD.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.
 
 # This is the root build file for GN. GN will start processing by loading this
 # file, and recursively load all dependencies until all dependencies are either
 # resolved or known not to exist (which will cause the build to fail). So if
 # you add a new build file, there must be some path of dependencies from this
 # file to your new one or GN won't know about it.
 
@@ skipping 91 matching lines @@
 if (is_win) {
   group("chrome_official_builder_no_unittests") {
     deps = [
       "//chrome/installer/gcapi",
       "//chrome/installer/mini_installer",
       "//components/policy:pack_policy_templates",
       "//courgette",
       "//courgette:copy_courgette_binaries",
       "//remoting/webapp",
     ]
+
     if (target_cpu == "x86") {
-      deps += [ "//courgette(//build/toolchain/win:x64)" ]
-
+      if (is_clang) {
+        deps += [ "//courgette(//build/toolchain/win:clang_x64)" ]
+      } else {
+        deps += [ "//courgette(//build/toolchain/win:x64)" ]

[chrisha, 2016/07/28 15:29:57]

I'm not 100% up on how to do things in GN. Does it make sense to have
conditional logic related to courgette in THIS build file? Or should Courgette's
GN file have the appropriate logic gated on 'is_clang'?

[etienneb, 2016/07/28 15:35:39]

I was expecting a cleaner way to do this:

  deps += [ "//courgette($host_compiler)" ]

But, I'm not convince what is the clean way. I hope brettw@ has some inside for
me.

But, I agree... is_clang here is working, but doesn't sound clean.

+      }
       if (is_chrome_branded) {
         deps += [ "//remoting/host:remoting_host_installation" ]
       }
     }
   }
 
   group("chrome_official_builder") {
     testonly = true
 
     deps = [
@@ skipping 916 matching lines @@
   assert(target_name != "")  # Mark as used.
   sources = invoker.actual_sources
   assert(
       sources == invoker.actual_sources,
       "Do not use a platform name in your output directory (found \"$root_build_dir\"). http://crbug.com/548283")
 }
 
 assert_valid_out_dir("_unused") {
   actual_sources = [ "$root_build_dir/foo" ]
 }