ninja windows: Support magic idl build rules

test/win/idl-rules/basic-idl.gyp

+# Copyright (c) 2012 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.
+
+{
+  'variables': {
+    'midl_out_dir': '<(SHARED_INTERMEDIATE_DIR)',
+  },
+  'targets': [
+    {
+      'target_name': 'idl_test',
+      'type': 'executable',
+      'sources': [
+        'history_indexer.idl',
+        '<(midl_out_dir)/history_indexer.h',
+        '<(midl_out_dir)/history_indexer_i.c',
+        'history_indexer_user.cc',
+      ],
+      'include_dirs': [
+        '<(midl_out_dir)',
+      ],
+      'msvs_settings': {
+        'VCMIDLTool': {
+          'OutputDirectory': '<(midl_out_dir)',
+          'HeaderFileName': '<(RULE_INPUT_ROOT).h',
+         },
+      },
+    },
+  ],
+}