Safe headphone volume limit.

Added safe headphone volume limit in config.xml.

Bug 7379739.

Change-Id: Ibd813f2cffcfd08294cab70ae819d7b34406e9fe
diff --git a/overlay/frameworks/base/core/res/res/values/config.xml b/overlay/frameworks/base/core/res/res/values/config.xml
index 09c7ed3..5f8f53f 100644
--- a/overlay/frameworks/base/core/res/res/values/config.xml
+++ b/overlay/frameworks/base/core/res/res/values/config.xml
@@ -227,4 +227,8 @@
 
     <!--  Maximum number of supported users -->
     <integer name="config_multiuserMaximumUsers">8</integer>
+
+    <!-- reference volume index for music stream to limit headphone volume and display warning -->
+    <integer name="config_safe_media_volume_index">6</integer>
+
 </resources>