GN: Factor "stamp" and "copy" details out of toolchains

build/toolchain/win/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.
 
 declare_args() {
   # Path to the directory containing the VC binaries for the right
   # combination of host and target architectures. Currently only the
   # 64-bit host toolchain is supported, with either 32-bit or 64-bit targets.
   # If vc_bin_dir is not specified on the command line (and it normally
   # isn't), we will dynamically determine the right value to use at runtime.
   vc_bin_dir = ""
 }
 
 import("//build/config/win/visual_studio_version.gni")
 import("//build/toolchain/goma.gni")
+import("//build/toolchain/toolchain.gni")
 
 # Should only be running on Windows.
 assert(is_win)
 
 # Setup the Visual Studio state.
 #
 # 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.
 gyp_win_tool_path =
@@ skipping 181 matching lines @@
       description = "LINK {{output}}"
       outputs = [
         "{{root_out_dir}}/{{target_output_name}}{{output_extension}}",
       ]
 
       # The use of inputs_newline is to work around a fixed per-line buffer
       # size in the linker.
       rspfile_content = "{{inputs_newline}} {{libs}} {{solibs}} {{ldflags}}"
     }
 
+    # These two are really entirely generic, but have to be repeated in
+    # each toolchain because GN doesn't allow a template to be used here.
+    # See //build/toolchain/toolchain.gni for details.
     tool("stamp") {
-      command = "$python_path gyp-win-tool stamp {{output}}"
-      description = "STAMP {{output}}"
+      command = stamp_command
+      description = stamp_description
     }
-
     tool("copy") {
-      command =
-          "$python_path gyp-win-tool recursive-mirror {{source}} {{output}}"
-      description = "COPY {{source}} {{output}}"
+      command = copy_command
+      description = copy_description
     }
 
     # When invoking this toolchain not as the default one, these args will be
     # passed to the build. They are ignored when this is the default toolchain.
     toolchain_args() {
       current_cpu = invoker.current_cpu
       if (defined(invoker.is_clang)) {
         is_clang = invoker.is_clang
       }
       current_os = invoker.current_os
@@ skipping 52 matching lines @@
 }
 
 msvc_toolchain("winrt_x64") {
   environment = "environment.winrt_x64"
   cl = "${goma_prefix}\"${vc_bin_dir}/cl.exe\""
   is_clang = false
 
   current_cpu = "x64"
   current_os = current_os
 }