remove unused parameter

src/app/debugger/debuggerUI/Slider.js

@@ -4,9 +4,8 @@ var EventManager = remixLib.EventManager
 var yo = require('yo-yo')
 
 class Slider {
-  constructor (_traceManager, _stepOverride) {
+  constructor (_stepOverride) {
     this.event = new EventManager()
-    this.traceManager = _traceManager
     this.max
     this.disabled = true
     this.view

src/app/debugger/debuggerUI/StepManager.js

@@ -26,7 +26,7 @@ function StepManager (_parent, _traceManager) {
     })
   })
 
-  this.slider = new Slider(this.traceManager, (step) => {
+  this.slider = new Slider((step) => {
     return this.solidityMode ? this.resolveToReducedTrace(step, 0) : step
   })
   this.slider.event.register('moved', this, function (step) {