Adding rateUpdates field to WebAudioSound class to keep track of all rate changes

Author: pavle-goloskokovic

v3/src/sound/webaudio/WebAudioSound.js

@@ -55,6 +55,13 @@ var WebAudioSound = new Class({
          * @property {number} pausedTime
          */
         this.pausedTime = 0;
+        /**
+         * An array where we keep track of all rate updates during playback.
+         *
+         * @private
+         * @property {{ time: number, rate: number }[]} rateUpdates
+         */
+        this.rateUpdates = [];
         /**
          * Used for keeping track when sound source playback has ended
          * so it's state can be updated accordingly.