[DevTools] Do not expose agents on Target

third_party/WebKit/Source/devtools/front_end/sdk/LogModel.js

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 /**
  * @implements {Protocol.LogDispatcher}
  */
 SDK.LogModel = class extends SDK.SDKModel {
   /**
    * @param {!SDK.Target} target
+   * @param {!Protocol.Dispatcher} dispatcher
    */
-  constructor(target) {
-    super(target);
-    target.registerLogDispatcher(this);
-    this._logAgent = target.logAgent();
+  constructor(target, dispatcher) {
+    super(target, dispatcher);
+    dispatcher.registerLogDispatcher(this);
+    this._logAgent = dispatcher.logAgent();
     this._logAgent.enable();
     if (!Host.isUnderTest()) {
       this._logAgent.startViolationsReport([
         {name: 'longTask', threshold: 200}, {name: 'longLayout', threshold: 30}, {name: 'blockedEvent', threshold: 100},
         {name: 'blockedParser', threshold: -1}, {name: 'handler', threshold: 150},
         {name: 'recurringHandler', threshold: 50}, {name: 'discouragedAPIUse', threshold: -1}
       ]);
     }
   }
 
   /**
    * @override
    * @param {!Protocol.Log.LogEntry} payload
    */
   entryAdded(payload) {
     this.dispatchEventToListeners(SDK.LogModel.Events.EntryAdded, {logModel: this, entry: payload});
   }
 
   requestClear() {
     this._logAgent.clear();
   }
 };
 
 SDK.SDKModel.register(SDK.LogModel, SDK.Target.Capability.Log, true);
 
 /** @enum {symbol} */
 SDK.LogModel.Events = {
   EntryAdded: Symbol('EntryAdded')
 };