Integrate ninja build with Visual Studio

test/msvs/external_builder/external.gyp

+# Copyright (c) 2013 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+{
+  'variables': {
+    # the test driver switches this flag when testing external builder
+    'use_external_builder%': 0,
+  },
+  'targets': [
+    {
+      'target_name': 'external',
+      'type': 'executable',
+      'sources': [
+        'hello.cpp',
+        'hello.z',
+      ],
+      'rules': [
+        {
+          'rule_name': 'test_rule',
+          'extension': 'z',
+          'outputs': [
+            'msbuild_rule.out',
+          ],
+          'action': [
+            'python',
+            'msbuild_rule.py',
+            '<(RULE_INPUT_PATH)',
+            'a', 'b', 'c',
+          ],
+          'msvs_cygwin_shell': 0,
+        },
+      ],
+      'actions': [
+        {
+          'action_name': 'test action',
+          'inputs': [
+            'msbuild_action.py',
+          ],
+          'outputs': [
+            'msbuild_action.out',
+          ],
+          'action': [
+            'python',
+            '<@(_inputs)',
+            'x', 'y', 'z',
+          ],
+          'msvs_cygwin_shell': 0,
+        },
+      ],
+      'conditions': [
+        ['use_external_builder==1', {
+          'msvs_external_builder': 'test',
+          'msvs_external_builder_build_cmd': [
+            'python',
+            'external_builder.py',
+            'build', '1', '2', '3',
+          ],
+          'msvs_external_builder_clean_cmd': [
+            'python',
+            'external_builder.py',
+            'clean', '4', '5',
+          ],
+        }],
+      ],
+    },
+  ],
+}