Introduce shared_memory_support media target for PPAPI

media/shared_memory_support.gypi

+# 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': {
+    'chromium_code': 1,
+    # These are defined here because we need to build this library both for
+    # the general media pipeline and again for the untrusted NaCl target.
+    'shared_memory_support_sources': [
+      'audio/audio_parameters.cc',
+      'audio/audio_parameters.h',
+      'audio/shared_memory_util.cc',
+      'audio/shared_memory_util.h',
+      'base/audio_bus.cc',
+      'base/audio_bus.h',
+      'base/channel_layout.cc',
+      'base/channel_layout.h',
+      'base/limits.h',
+      'base/media_export.h',
+    ],
+  },
+}