DevTools: Refactor network panel overview

Source/devtools/front_end/network/NetworkTimeCalculator.js

Index: Source/devtools/front_end/network/NetworkTimeCalculator.js
diff --git a/Source/devtools/front_end/network/NetworkTimeCalculator.js b/Source/devtools/front_end/network/NetworkTimeCalculator.js
index 08546afe1a1c1f4b4e2f2f324f6f8d06f4cc9e95..b6e278dcb07ef4ff369777575e6f83bf4449df52 100644
--- a/Source/devtools/front_end/network/NetworkTimeCalculator.js
+++ b/Source/devtools/front_end/network/NetworkTimeCalculator.js
@@ -309,22 +309,33 @@ WebInspector.NetworkTimeCalculator.prototype = {
      */
     updateBoundaries: function(request)
     {
-        var lowerBound;
-        if (this.startAtZero)
-            lowerBound = 0;
-        else
-            lowerBound = this._lowerBound(request);
-
-        if (lowerBound !== -1 && (typeof this._minimumBoundary === "undefined" || lowerBound < this._minimumBoundary)) {
-            this._minimumBoundary = lowerBound;
-            this._boundaryChanged();
-        }
-
+        var lowerBound = this._lowerBound(request);
         var upperBound = this._upperBound(request);
-        if (upperBound !== -1 && (typeof this._maximumBoundary === "undefined" || upperBound > this._maximumBoundary)) {
-            this._maximumBoundary = upperBound;
+        var changed = false;
+        if (lowerBound !== -1 || this.startAtZero)
+            changed = this._extendBoundariesToIncludeTimestamp(this.startAtZero ? 0 : lowerBound);
+        if (upperBound !== -1)
+            changed = this._extendBoundariesToIncludeTimestamp(upperBound) || changed;
+        if (changed)
             this._boundaryChanged();
+    },
+
+    /**
+     * @param {number} timestamp
+     * @return {boolean}
+     */
+    _extendBoundariesToIncludeTimestamp: function(timestamp)
+    {
+        var previousMinimumBoundary = this._minimumBoundary;
+        var previousMaximumBoundary = this._maximumBoundary;
+        if (typeof this._minimumBoundary === "undefined" || typeof this._maximumBoundary === "undefined") {
+            this._minimumBoundary = timestamp;
+            this._maximumBoundary = timestamp + 1;
+        } else {
+            this._minimumBoundary = Math.min(timestamp, this._minimumBoundary);
+            this._maximumBoundary = Math.max(timestamp, this._minimumBoundary + 1, this._maximumBoundary);
         }
+        return previousMinimumBoundary !== this._minimumBoundary || previousMaximumBoundary !== this._maximumBoundary;
     },
 
     /**