DevTools: Do not show network pane on Timeline when there're no network activity

third_party/WebKit/Source/devtools/front_end/timeline/TimelineNetworkFlameChart.js

Index: third_party/WebKit/Source/devtools/front_end/timeline/TimelineNetworkFlameChart.js
diff --git a/third_party/WebKit/Source/devtools/front_end/timeline/TimelineNetworkFlameChart.js b/third_party/WebKit/Source/devtools/front_end/timeline/TimelineNetworkFlameChart.js
index 1243f4681918a986b20219937d85e2631b7ca8c6..bb639f0ca3a0fc507e5ab66550da9f8849d3d91c 100644
--- a/third_party/WebKit/Source/devtools/front_end/timeline/TimelineNetworkFlameChart.js
+++ b/third_party/WebKit/Source/devtools/front_end/timeline/TimelineNetworkFlameChart.js
@@ -11,13 +11,9 @@ Timeline.TimelineFlameChartNetworkDataProvider = class {
    * @param {!TimelineModel.TimelineModel} model
    */
   constructor(model) {
-    this.reset();
     this._font = '11px ' + Host.fontFamily();
     this._model = model;
-    var loadingCategory = Timeline.TimelineUIUtils.categories()['loading'];
-    this._waitingColor = loadingCategory.childColor;
-    this._processingColor = loadingCategory.color;
-
+    this.reset();
     this._style = {
       padding: 4,
       height: 17,
@@ -33,6 +29,14 @@ Timeline.TimelineFlameChartNetworkDataProvider = class {
   }
 
   /**
+   * @return {boolean}
+   */
+  isEmpty() {
+    this.timelineData();
+    return this._maxLevel === 0;
+  }
+
+  /**
    * @override
    * @return {number}
    */
@@ -349,7 +353,7 @@ Timeline.TimelineFlameChartNetworkDataProvider = class {
    * @return {number}
    */
   preferredHeight() {
-    return this._style.height * (this._group.expanded ? Number.constrain(this._maxLevel + 1, 4, 8) : 2);
+    return this._style.height * (this._group.expanded ? Number.constrain(this._maxLevel + 1, 4, 8.5) : 1);
   }
 
   /**