Move the mini_installer_version rule to its own gyp file.

chrome/installer/mini_installer_version.gyp

+# Copyright (c) 2015 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': {
+    'chromium_code': 1,
+    'version_py': '<(DEPTH)/build/util/version.py',
+    'version_path': '../../chrome/VERSION',
+    'lastchange_path': '<(DEPTH)/build/util/LASTCHANGE',
+    'branding_dir': '../app/theme/<(branding_path_component)',
+  },
+  'conditions': [
+    ['OS=="win"', {
+      'targets': [
+      {
+        'target_name': 'mini_installer_version',
+        'type': 'none',
+        'rules': [
+          {
+            'rule_name': 'mini_installer_version',
+            'extension': 'version',
+            'variables': {
+              'template_input_path': 'mini_installer/mini_installer_exe_version.rc.version',
+            },
+            'inputs': [
+              '<(template_input_path)',
+              '<(version_path)',
+              '<(lastchange_path)',
+              '<(branding_dir)/BRANDING',
+            ],
+            'outputs': [
+              '<(PRODUCT_DIR)/mini_installer_exe_version.rc',
+            ],
+            'action': [
+              'python', '<(version_py)',
+              '-f', '<(version_path)',
+              '-f', '<(lastchange_path)',
+              '-f', '<(branding_dir)/BRANDING',
+              '<(template_input_path)',
+              '<@(_outputs)',
+            ],
+            'process_outputs_as_sources': 1,
+            'message': 'Generating version information'
+          },
+        ],
+      }],
+    }],
+  ],
+}