[Devtools] NetworkLogView now uses NetworkLog as source of truth.

third_party/WebKit/Source/devtools/front_end/network/NetworkFrameGrouper.js

Index: third_party/WebKit/Source/devtools/front_end/network/NetworkFrameGrouper.js
diff --git a/third_party/WebKit/Source/devtools/front_end/network/NetworkFrameGrouper.js b/third_party/WebKit/Source/devtools/front_end/network/NetworkFrameGrouper.js
index 007554264c570e3b4e7886f4f075084d862a75a7..1d2e0e2fb9980e3950b5c8e417a39a12685e7548 100644
--- a/third_party/WebKit/Source/devtools/front_end/network/NetworkFrameGrouper.js
+++ b/third_party/WebKit/Source/devtools/front_end/network/NetworkFrameGrouper.js
@@ -11,8 +11,7 @@ Network.NetworkFrameGrouper = class {
    */
   constructor(parentView) {
     this._parentView = parentView;
-    /** @type {!Map<!SDK.ResourceTreeFrame, !Network.FrameGroupNode>} */
-    this._activeGroups = new Map();
+    this._frameGroupNodeSymbol = Symbol('FrameGroupNode');
   }
 
   /**
@@ -24,20 +23,13 @@ Network.NetworkFrameGrouper = class {
     var frame = SDK.ResourceTreeModel.frameForRequest(request);
     if (!frame || frame.isMainFrame())
       return null;
-    var groupNode = this._activeGroups.get(frame);
+    var groupNode = frame[this._frameGroupNodeSymbol];
     if (groupNode)
       return groupNode;
     groupNode = new Network.FrameGroupNode(this._parentView, frame);
-    this._activeGroups.set(frame, groupNode);
+    frame[this._frameGroupNodeSymbol] = groupNode;
     return groupNode;
   }
-
-  /**
-   * @override
-   */
-  reset() {
-    this._activeGroups.clear();
-  }
 };
 
 Network.FrameGroupNode = class extends Network.NetworkGroupNode {