Revert of Remove gyp-win-tool.

build/toolchain/win/BUILD.gn

Index: build/toolchain/win/BUILD.gn
diff --git a/build/toolchain/win/BUILD.gn b/build/toolchain/win/BUILD.gn
index ccc0a9435f6fd2ab5da717e0b13066cdab60cd21..d6364bd844f8c48b397bbc2ab09fa86973639583 100644
--- a/build/toolchain/win/BUILD.gn
+++ b/build/toolchain/win/BUILD.gn
@@ -17,6 +17,10 @@
 # Its arguments are the VS path and the compiler wrapper tool. It will write
 # "environment.x86" and "environment.x64" to the build directory and return a
 # list to us.
+
+# TODO bug 642014 remove this when all users of the script have been removed.
+gyp_win_tool_path =
+    rebase_path("//tools/gyp/pylib/gyp/win_tool.py", root_build_dir)
 
 # This tool will is used as a wrapper for various commands below.
 tool_wrapper_path = rebase_path("tool_wrapper.py", root_build_dir)
@@ -314,6 +318,7 @@
   x86_toolchain_data = exec_script("setup_toolchain.py",
                                    [
                                      visual_studio_path,
+                                     gyp_win_tool_path,
                                      windows_sdk_path,
                                      visual_studio_runtime_dirs,
                                      "x86",
@@ -347,6 +352,7 @@
 x64_toolchain_data = exec_script("setup_toolchain.py",
                                  [
                                    visual_studio_path,
+                                   gyp_win_tool_path,
                                    windows_sdk_path,
                                    visual_studio_runtime_dirs,
                                    "x64",