[DevTools] Remove Common.Event.target field.

third_party/WebKit/Source/devtools/front_end/bindings/BlackboxManager.js

 // Copyright 2014 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 {SDK.TargetManager.Observer}
  * @unrestricted
  */
 Bindings.BlackboxManager = class {
   /**
    * @param {!Bindings.DebuggerWorkspaceBinding} debuggerWorkspaceBinding
@@ skipping 286 matching lines @@
   }
 
   _patternChangeFinishedForTests() {
     // This method is sniffed in tests.
   }
 
   /**
    * @param {!Common.Event} event
    */
   _globalObjectCleared(event) {
-    var debuggerModel = /** @type {!SDK.DebuggerModel} */ (event.target);
+    var debuggerModel = /** @type {!SDK.DebuggerModel} */ (event.data);
     this._debuggerModelData.delete(debuggerModel);
     this._isBlackboxedURLCache.clear();
   }
 
   /**
    * @param {!Common.Event} event
    */
   _parsedScriptSource(event) {
     var script = /** @type {!SDK.Script} */ (event.data);
     this._addScript(script);
@@ skipping 105 matching lines @@
       if (scheme === 'chrome-extension')
         prefix += parsedURL.host + '\\b';
       prefix += '.*';
     }
     return prefix + name.escapeForRegExp() + (url.endsWith(name) ? '$' : '\\b');
   }
 };
 
 /** @type {!Bindings.BlackboxManager} */
 Bindings.blackboxManager;