[DevTools] Do not expose agents on Target

third_party/WebKit/Source/devtools/front_end/coverage/CoverageModel.js

 // Copyright (c) 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.
 
 /** @typedef {{startOffset: number, endOffset: number, count: number}} */
 Coverage.RangeUseCount;
 
 /** @typedef {{end: number, count: (number|undefined)}} */
 Coverage.CoverageSegment;
 
 /**
  * @enum {number}
  */
 Coverage.CoverageType = {
   CSS: (1 << 0),
   JavaScript: (1 << 1),
 };
 
-Coverage.CoverageModel = class extends SDK.SDKModel {
+Coverage.CoverageModel = class {
   /**
    * @param {!SDK.Target} target
    */
   constructor(target) {
-    super(target);
+    this._target = target;

[caseq, 2017/04/29 02:12:53]

Is it still necessary?

     this._cpuProfilerModel = target.model(SDK.CPUProfilerModel);
     this._cssModel = target.model(SDK.CSSModel);
     this._debuggerModel = target.model(SDK.DebuggerModel);
 
     /** @type {!Map<string, !Coverage.URLCoverageInfo>} */
     this._coverageByURL = new Map();
   }
 
   /**
    * @return {boolean}
@@ skipping 331 matching lines @@
     this._usedSize = 0;
 
     var last = 0;
     for (var segment of this._segments) {
       if (segment.count)
         this._usedSize += segment.end - last;
       last = segment.end;
     }
   }
 };