DevTools: add missing check for null script in SourceMapNamesResolver

third_party/WebKit/Source/devtools/front_end/sources/SourceMapNamesResolver.js

 // Copyright 2016 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.
 Sources.SourceMapNamesResolver = {};
 
 Sources.SourceMapNamesResolver._cachedMapSymbol = Symbol('cache');
 Sources.SourceMapNamesResolver._cachedIdentifiersSymbol = Symbol('cachedIdentifiers');
 
 /**
  * @unrestricted
@@ skipping 13 matching lines @@
 
 /**
  * @param {!SDK.DebuggerModel.Scope} scope
  * @return {!Promise<!Array<!Sources.SourceMapNamesResolver.Identifier>>}
  */
 Sources.SourceMapNamesResolver._scopeIdentifiers = function(scope) {
   var startLocation = scope.startLocation();
   var endLocation = scope.endLocation();
 
   if (scope.type() === Protocol.Debugger.ScopeType.Global || !startLocation || !endLocation ||
-      !startLocation.script().sourceMapURL || (startLocation.script() !== endLocation.script()))
+      !startLocation.script() || !startLocation.script().sourceMapURL ||
+      (startLocation.script() !== endLocation.script()))
     return Promise.resolve(/** @type {!Array<!Sources.SourceMapNamesResolver.Identifier>}*/ ([]));
 
   var script = startLocation.script();
   return script.requestContent().then(onContent);
 
   /**
    * @param {?string} content
    * @return {!Promise<!Array<!Sources.SourceMapNamesResolver.Identifier>>}
    */
   function onContent(content) {
@@ skipping 280 matching lines @@
 
 /**
  * @param {!SDK.DebuggerModel.Scope} scope
  * @return {!SDK.RemoteObject}
  */
 Sources.SourceMapNamesResolver.resolveScopeInObject = function(scope) {
   var startLocation = scope.startLocation();
   var endLocation = scope.endLocation();
 
   if (scope.type() === Protocol.Debugger.ScopeType.Global || !startLocation || !endLocation ||
-      !startLocation.script().sourceMapURL || startLocation.script() !== endLocation.script())
+      !startLocation.script() || !startLocation.script().sourceMapURL ||
+      startLocation.script() !== endLocation.script())
     return scope.object();
 
   return new Sources.SourceMapNamesResolver.RemoteObject(scope);
 };
 
 /**
  * @unrestricted
  */
 Sources.SourceMapNamesResolver.RemoteObject = class extends SDK.RemoteObject {
   /**
@@ skipping 185 matching lines @@
   }
 
   /**
    * @override
    * @return {boolean}
    */
   isNode() {
     return this._object.isNode();
   }
 };