[Android] Support third part media player on Crosswalk

A requirement from an important customer who want to forward web resources with proxy
on Crosswalk, but android system MediaPlayer can't set a proxy with a standard API.
The ExoMediaPlayer is playing videos and music is a popular activity on Android devices,
and it can be configured with proxy.
https://developer.android.com/guide/topics/media/exoplayer.html

BUG=XWALK-6770

media/base/android/java/src/org/chromium/media/ExternalMediaPlayer.java

@@ -0,0 +1,123 @@
+// 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.
+
+package org.chromium.media;
+
+import android.content.Context;
+import android.media.MediaPlayer;
+import android.media.MediaPlayer.TrackInfo;
+import android.net.Uri;
+import android.view.Surface;
+
+import org.chromium.base.Log;
+
+import java.io.FileDescriptor;
+import java.io.IOException;
+import java.util.Map;
+
+/**
+* Use Android system MediaPlayer by default.
+*/
+public class ExternalMediaPlayer {
+    private static final String TAG = "ExternalMediaPlayer";
+
+    private MediaPlayer mPlayer;
+
+    protected MediaPlayer getLocalPlayer() {
+        if (mPlayer == null) {
+            mPlayer = new MediaPlayer();
+            Log.d(TAG, "Create a Android System Media Player.");
+        }
+        return mPlayer;
+    }
+
+    public void setSurface(Surface surface) {
+        getLocalPlayer().setSurface(surface);
+    }
+
+    public void setDataSource(Context context, Uri uri, Map<String, String> headers)
+            throws Exception {
+        getLocalPlayer().setDataSource(context, uri, headers);
+    }
+
+    public void setDataSource(FileDescriptor fd, long offset, long length) throws IOException {
+        getLocalPlayer().setDataSource(fd, offset, length);
+    }
+
+    public void setDataSource(Context context, Uri uri) throws IOException {
+        getLocalPlayer().setDataSource(context, uri);
+    }
+
+    public void prepareAsync() throws IllegalStateException {
+        getLocalPlayer().prepareAsync();
+    }
+
+    public TrackInfo[] getTrackInfo() throws RuntimeException {
+        return getLocalPlayer().getTrackInfo();
+    }
+
+    public boolean isPlaying() {
+        return getLocalPlayer().isPlaying();
+    }
+
+    public int getVideoWidth() {
+        return getLocalPlayer().getVideoWidth();
+    }
+
+    public int getVideoHeight() {
+        return getLocalPlayer().getVideoHeight();
+    }
+
+    public int getCurrentPosition() {
+        return getLocalPlayer().getCurrentPosition();
+    }
+
+    public int getDuration() {
+        return getLocalPlayer().getDuration();
+    }
+
+    public void release() {
+        getLocalPlayer().release();
+    }
+
+    public void setVolume(float volume1, float volume2) {
+        getLocalPlayer().setVolume((float) volume1, (float) volume2);
+    }
+
+    public void start() {
+        getLocalPlayer().start();
+    }
+
+    public void pause() {
+        getLocalPlayer().pause();
+    }
+
+    public void seekTo(int msec) {
+        getLocalPlayer().seekTo(msec);
+    }
+
+    public void setOnBufferingUpdateListener(MediaPlayer.OnBufferingUpdateListener listener) {
+        getLocalPlayer().setOnBufferingUpdateListener(listener);
+    }
+
+    public void setOnCompletionListener(MediaPlayer.OnCompletionListener listener) {
+        getLocalPlayer().setOnCompletionListener(listener);
+    }
+
+    public void setOnErrorListener(MediaPlayer.OnErrorListener listener) {
+        getLocalPlayer().setOnErrorListener(listener);
+    }
+
+    public void setOnPreparedListener(MediaPlayer.OnPreparedListener listener) {
+        getLocalPlayer().setOnPreparedListener(listener);
+    }
+
+    public void setOnSeekCompleteListener(MediaPlayer.OnSeekCompleteListener listener) {
+        getLocalPlayer().setOnSeekCompleteListener(listener);
+    }
+
+    public void setOnVideoSizeChangedListener(MediaPlayer.OnVideoSizeChangedListener listener) {
+        getLocalPlayer().setOnVideoSizeChangedListener(listener);
+    }
+}

media/base/android/java/src/org/chromium/media/MediaPlayerBridge.java

@@ -35,12 +35,18 @@
 */
 @JNINamespace("media")
 public class MediaPlayerBridge {
-
+    /**
+    * Give the host application a chance to take over MeidaPlayer.
+    */
     public static class ResourceLoadingFilter {
         public boolean shouldOverrideResourceLoading(
-                MediaPlayer mediaPlayer, Context context, Uri uri) {
+                ExternalMediaPlayer mediaPlayer, Context context, Uri uri) {
             return false;
         }
+
+        public ExternalMediaPlayer getExternalMediaPlayer() {
+            return null;
+        }
     }
 
     private static ResourceLoadingFilter sResourceLoadFilter = null;
@@ -54,7 +60,7 @@ public static void setResourceLoadingFilter(ResourceLoadingFilter filter) {
     // Local player to forward this to. We don't initialize it here since the subclass might not
     // want it.
     private LoadDataUriTask mLoadDataUriTask;
-    private MediaPlayer mPlayer;
+    private ExternalMediaPlayer mPlayer;
     private long mNativeMediaPlayerBridge;
 
     @CalledByNative
@@ -78,9 +84,9 @@ protected void destroy() {
         mNativeMediaPlayerBridge = 0;
     }
 
-    protected MediaPlayer getLocalPlayer() {
+    protected ExternalMediaPlayer getLocalPlayer() {
         if (mPlayer == null) {
-            mPlayer = new MediaPlayer();
+            mPlayer = sResourceLoadFilter.getExternalMediaPlayer();
         }
         return mPlayer;
     }
@@ -202,9 +208,9 @@ protected boolean setDataSource(
             headersMap.put("allow-cross-domain-redirect", "false");
         }
         try {
-            if (sResourceLoadFilter != null &&
-                    sResourceLoadFilter.shouldOverrideResourceLoading(
-                            getLocalPlayer(), context, uri)) {
+            if (sResourceLoadFilter != null
+                    && sResourceLoadFilter.shouldOverrideResourceLoading(
+                               getLocalPlayer(), context, uri)) {
                 return true;
             }
             getLocalPlayer().setDataSource(context, uri, headersMap);
@@ -372,7 +378,7 @@ private boolean canSeekBackward() {
      */
     @CalledByNative
     protected AllowedOperations getAllowedOperations() {
-        MediaPlayer player = getLocalPlayer();
+        ExternalMediaPlayer player = getLocalPlayer();
         boolean canPause = true;
         boolean canSeekForward = true;
         boolean canSeekBackward = true;