Remove webrtc/examples/android/media_demo.

webrtc/examples/android/media_demo/README

-This directory contains a sample app for sending and receiving audio
-on Android. It further lets you enable and disable some call quality
-enhancements such as echo cancellation, noise suppression etc.
-
-Prerequisites:
-- Make sure gclient is checking out tools necessary to target Android: your
-  .gclient file should contain a line like:
-  target_os = ['android']
-  Make sure to re-run gclient sync after adding this to download the tools.
-- Env vars need to be set up to target Android; easiest way to do this is to run
-  (from the libjingle trunk directory):
-  . ./build/android/envsetup.sh
-  Note that this clobbers any previously-set $GYP_DEFINES so it must be done
-  before the next item.
-- Set up webrtc-related GYP variables:
-  export GYP_DEFINES="$GYP_DEFINES java_home=</path/to/JDK>"
-- Finally, run "gclient runhooks" to generate Android-targeting .ninja files.
-
-Example of building the app:
-cd <path/to/repository>/trunk
-ninja -C out/Debug WebRTCDemo
-
-It can then be installed and run on the device:
-adb install -r out/Debug/WebRTCDemo-debug.apk