mojo: Get mojo:leveldb and mojo:filesystem compiled into content.

mojo/mojo_platform_handle.gyp

+# Copyright 2016 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': {
+    # This turns on e.g. the filename-based detection of which
+    # platforms to include source files on (e.g. files ending in
+    # _mac.h or _mac.cc are only compiled on MacOSX).
+    'chromium_code': 1,
+  },
+  'targets': [
+    {
+      # GN version: //mojo/platform_handle:platform_handle/platform_handle_impl
+      'target_name': 'platform_handle',
+      'type': 'static_library',
+      'include_dirs': [
+        '../..',
+      ],
+      'defines': [
+        'PLATFORM_HANDLE_IMPLEMENTATION'
+      ],
+      'sources': [
+        'platform_handle/platform_handle.h',
+        'platform_handle/platform_handle_functions.h',
+        'platform_handle/platform_handle_functions.cc',
+      ],
+      'dependencies': [
+        'mojo_edk.gyp:mojo_system_impl',
+        'mojo_public.gyp:mojo_cpp_bindings',
+      ]
+    }
+  ]
+}