CB-6153 Add a preference for controlling hardware button audio stream (DefaultVolumeStream)

This, along with the commit to the audio plugin, makes it so that by
default apps control the ringer volume, but when any audio players are
active, the media volume is controlled.

Author: agrieve

framework/src/org/apache/cordova/CordovaActivity.java

@@ -20,6 +20,7 @@ Licensed to the Apache Software Foundation (ASF) under one
 
 import java.util.ArrayList;
 import java.util.HashMap;
+import java.util.Locale;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 
@@ -346,9 +347,11 @@ public void init(CordovaWebView webView, CordovaWebViewClient webViewClient, Cor
         }
         createViews();
 
-        // TODO: Make this a preference (CB-6153)
-        // Setup the hardware volume controls to handle volume control
-        setVolumeControlStream(AudioManager.STREAM_MUSIC);
+        // Wire the hardware volume controls to control media if desired.
+        String volumePref = preferences.getString("DefaultVolumeStream", "");
+        if ("media".equals(volumePref.toLowerCase(Locale.ENGLISH))) {
+            setVolumeControlStream(AudioManager.STREAM_MUSIC);
+        }
     }
 
     /**