[gnome-shell] volume: Show overamplified icon when in overdrive

[Florian Müllner <fmuellner src gnome org>]

commit 6217c3b88d837a8d03e524f0dcb89e8b7c5ee5d5
Author: Didier Roche <didrocks ubuntu com>
Date:   Fri Feb 9 15:10:16 2018 +0100

    volume: Show overamplified icon when in overdrive
    
    Show an overamplified volume icon if volume is louder the max normalized one.
    Use a similar logic as gnome-settings-daemon to delimit values, restricted
    to output.
    The purpose is to help users remember that visiting some websites or
    using some apps can get LOUD.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=790280.

 js/ui/status/volume.js | 21 ++++++++++++++-------
 1 file changed, 14 insertions(+), 7 deletions(-)
---
diff --git a/js/ui/status/volume.js b/js/ui/status/volume.js
index b337e752d..00af791a6 100644
--- a/js/ui/status/volume.js
+++ b/js/ui/status/volume.js
@@ -158,17 +158,24 @@ var StreamSlider = new Lang.Class({
         if (!this._stream)
             return null;
 
+        let icons = ["audio-volume-muted-symbolic",
+                     "audio-volume-low-symbolic",
+                     "audio-volume-medium-symbolic",
+                     "audio-volume-high-symbolic",
+                     "audio-volume-overamplified-symbolic"];
+
         let volume = this._stream.volume;
+        let n;
         if (this._stream.is_muted || volume <= 0) {
-            return 'audio-volume-muted-symbolic';
+            n = 0;
         } else {
-            let n = Math.floor(3 * volume / this._control.get_vol_max_norm()) + 1;
-            if (n < 2)
-                return 'audio-volume-low-symbolic';
-            if (n >= 3)
-                return 'audio-volume-high-symbolic';
-            return 'audio-volume-medium-symbolic';
+            n = Math.ceil(3 * volume / this._control.get_vol_max_norm());
+            if (n < 1)
+                n = 1;
+            else if (n > 3)
+                n = 4;
         }
+        return icons[n];
     },
 
     getLevel() {