Fix some TODO(GYP) in the GN build.

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.
 
 # =============================================================================
 # PLATFORM SELECTION
 # =============================================================================
 #
 # There are two main things to set: "os" and "cpu". The "toolchain" is the name
 # of the GN thing that encodes combinations of these things.
@@ skipping 152 matching lines @@
       # support this?
       host_toolchain = "//build/toolchain/linux:clang_$host_cpu"
     } else if (is_clang) {
       host_toolchain = "//build/toolchain/linux:clang_$host_cpu"
     } else {
       host_toolchain = "//build/toolchain/linux:$host_cpu"
     }
   } else if (host_os == "mac") {
     host_toolchain = "//build/toolchain/mac:clang_$host_cpu"
   } else if (host_os == "win") {
-    # TODO(crbug.com/467159): win cross-compiles don't actually work yet, so
-    # use the target_cpu instead of the host_cpu.
+    # On Windows always use the target CPU for host builds. On the
+    # configurations we support this will always work and it saves build steps.
     if (is_clang) {
       host_toolchain = "//build/toolchain/win:clang_$target_cpu"
     } else {
       host_toolchain = "//build/toolchain/win:$target_cpu"
     }
   } else {
     assert(false, "Unsupported host_os: $host_os")
   }
 }
 
@@ skipping 435 matching lines @@
     forward_variables_from(invoker, "*", [ "visibility" ])
 
     # All shared libraries must have the sanitizer deps to properly link in
     # asan mode (this target will be empty in other cases).
     if (!defined(deps)) {
       deps = []
     }
     deps += [ "//build/config/sanitizers:deps" ]
   }
 }