Use javascript strict mode throughout a number of net-internals files.

chrome/browser/resources/net_internals/util.js

 // Copyright (c) 2011 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.
 
 /**
  * Inherit the prototype methods from one constructor into another.
  */
 function inherits(childCtor, parentCtor) {
   function tempCtor() {};
   tempCtor.prototype = parentCtor.prototype;
@@ skipping 125 matching lines @@
   if (!(object instanceof Object))
     return object;
   var copy = {};
   for (var key in object) {
     copy[key] = object[key];
   }
   return copy;
 }
 
 /**
+ * Helper to make sure singleton classes are not instantiated more than once.
+ */
+function assertFirstConstructorCall(ctor) {
+  // This is the variable which is set by cr.addSingletonGetter().
+  if (ctor.hasCreateFirstInstance_) {
+    throw Error('The class ' + ctor.name + ' is a singleton, and should ' +
+                'only be accessed using ' + ctor.name + '.getInstance().');
+  }
+  ctor.hasCreateFirstInstance_ = true;
+}
+
+/**
  * TablePrinter is a helper to format a table as ascii art or an HTML table.
  *
  * Usage: call addRow() and addCell() repeatedly to specify the data.
  *
  * addHeaderCell() can optionally be called to specify header cells for a
  * single header row.  The header row appears at the top of an HTML formatted
  * table, and uses thead and th tags.  In ascii tables, the header is separated
  * from the table body by a partial row of dashes.
  *
  * setTitle() can optionally be used to set a title that is displayed before
@@ skipping 211 matching lines @@
           linkNode.href = cell.link;
         } else {
           addTextNode(tableCell, cell.text);
         }
       }
     }
   }
   return table;
 };