Add setting to mute wireless charging sound.

Bug: 19538553
Change-Id: I1af971b35ae9eeb38d8ec38c57b22152095e2725
diff --git a/core/java/android/provider/Settings.java b/core/java/android/provider/Settings.java
index 293cf6f..3518f83 100644
--- a/core/java/android/provider/Settings.java
+++ b/core/java/android/provider/Settings.java
@@ -5951,6 +5951,12 @@
                 "wireless_charging_started_sound";
 
         /**
+         * Whether to play a sound for charging events.
+         * @hide
+         */
+        public static final String CHARGING_SOUNDS_ENABLED = "charging_sounds_enabled";
+
+        /**
          * Whether we keep the device on while the device is plugged in.
          * Supported values are:
          * <ul>