First pass on blink compiling for GN build

Source/build/scripts/scripts.gni

 # Copyright 2014 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.
 
 # All paths in this file should be absolute so targets in any directory can use
 # them without worrying about the current directory.
 _scripts_dir = "//third_party/WebKit/Source/build/scripts"
 
 scripts_for_in_files = [
   # jinja2/__init__.py contains version string, so sufficient as
@@ skipping 33 matching lines @@
   "$_scripts_dir/templates/ElementFactory.h.tmpl",
   "$_scripts_dir/templates/ElementWrapperFactory.cpp.tmpl",
   "$_scripts_dir/templates/ElementWrapperFactory.h.tmpl",
 ]
 
 make_element_type_helpers_files = make_qualified_names_files + [
   "$_scripts_dir/make_element_type_helpers.py",
   "$_scripts_dir/templates/ElementTypeHelpers.h.tmpl",
 ]
 
-# gperf_exe is relative to the build directory. Don't rebase it because on
-# Posix we want to run the system one on the path.
+# The executables are relative to the build directory. Don't rebase it because
+# on Posix we want to run the system one on the path.
 if (is_win) {
+  perl_exe = rebase_path("//third_party/perl/perl/bin/perl.exe", root_build_dir)
   gperf_exe = rebase_path("//third_party/gperf/bin/gperf.exe", root_build_dir)
+  bison_exe = rebase_path("//third_party/bison/bin/bison.exe", root_build_dir)
+  # Using cl instead of cygwin gcc cuts the processing time from
+  # 1m58s to 0m52s.
+  preprocessor = "--preprocessor \"cl.exe -nologo -EP -TP\""
 } else {
+  perl_exe = "perl"
   gperf_exe = "gperf"
+  bison_exe = "bison"
+  # We specify a preprocess so it happens locally and won't get
+  # distributed to goma.
+  # FIXME: /usr/bin/gcc won't exist on OSX forever. We want to
+  # use /usr/bin/clang once we require Xcode 4.x.
+  preprocessor = "--preprocessor \"/usr/bin/gcc -E -P -x c++\""
 }