DevTools: [Timeline] Reset Memory Overview pane when clear button is clicked

Source/devtools/front_end/TimelineOverviewPane.js

Index: Source/devtools/front_end/TimelineOverviewPane.js
diff --git a/Source/devtools/front_end/TimelineOverviewPane.js b/Source/devtools/front_end/TimelineOverviewPane.js
index 40d9a6b04dc76e611789909866539231038edf7d..51e3208bb444156a27c25d1d9b9b87ce74101a08 100644
--- a/Source/devtools/front_end/TimelineOverviewPane.js
+++ b/Source/devtools/front_end/TimelineOverviewPane.js
@@ -463,12 +463,12 @@ WebInspector.TimelineMemoryOverview = function(model)
 WebInspector.TimelineMemoryOverview.prototype = {
     update: function()
     {
+        this._resetCanvas();
+
         var records = this._model.records;
         if (!records.length)
             return;
 
-        this._resetCanvas();
-
         const lowerOffset = 3;
         var maxUsedHeapSize = 0;
         var minUsedHeapSize = 100000000000;
@@ -494,13 +494,11 @@ WebInspector.TimelineMemoryOverview.prototype = {
             histogram[x] = Math.max(histogram[x] || 0, y);
         });
 
-        var ctx = this._context;
-        this._clear(ctx);
-
         height++; // +1 so that the border always fit into the canvas area.
 
         var y = 0;
         var isFirstPoint = true;
+        var ctx = this._context;
         ctx.beginPath();
         ctx.moveTo(0, this._canvas.height);
         for (var x = 0; x < histogram.length; x++) {
@@ -531,12 +529,6 @@ WebInspector.TimelineMemoryOverview.prototype = {
         this._minHeapSizeLabel.textContent = Number.bytesToString(minUsedHeapSize);
     },
 
-    _clear: function(ctx)
-    {
-        ctx.fillStyle = "rgba(255,255,255,0.8)";
-        ctx.fillRect(0, 0, this._canvas.width, this._canvas.height);
-    },
-
     __proto__: WebInspector.TimelineOverviewBase.prototype
 }