Initial support for the desktop media pipeline on Android.

media/media_variables.gypi

+# Copyright 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.
+
+# Common media variables.
+{
+  'variables': {
+    'conditions': [
+      ['OS == "android" or OS == "ios"', {
+        # Android and iOS don't use FFmpeg or libvpx by default.
+        # Set media_use_ffmpeg=1 for Android builds to compile experimental
+        # support for FFmpeg and the desktop media pipeline.
+        'media_use_ffmpeg%': 0,
+        'media_use_libvpx%': 0,
+      }, {
+        'media_use_ffmpeg%': 1,
+        'media_use_libvpx%': 1,
+      }],
+    ],
+  },
+}