DevTools: [Console] use filtering to collapse and expand console groups

Source/devtools/front_end/sdk/ConsoleModel.js

 /*
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 240 matching lines @@
     isGroupMessage: function()
     {
         return this.type === WebInspector.ConsoleMessage.MessageType.StartGroup ||
             this.type === WebInspector.ConsoleMessage.MessageType.StartGroupCollapsed ||
             this.type === WebInspector.ConsoleMessage.MessageType.EndGroup;
     },
 
     /**
      * @return {boolean}
      */
+    isGroupStartMessage: function()
+    {
+        return this.type === WebInspector.ConsoleMessage.MessageType.StartGroup ||
+            this.type === WebInspector.ConsoleMessage.MessageType.StartGroupCollapsed;
+    },
+
+    /**
+     * @return {boolean}
+     */
     isErrorOrWarning: function()
     {
         return (this.level === WebInspector.ConsoleMessage.MessageLevel.Warning || this.level === WebInspector.ConsoleMessage.MessageLevel.Error);
     },
 
     /**
      * @return {!WebInspector.ConsoleMessage}
      */
     clone: function()
     {
@@ skipping 165 matching lines @@
     {
         if (!WebInspector.settings.preserveConsoleLog.get())
             this._console.clearMessages();
     }
 }
 
 /**
  * @type {!WebInspector.ConsoleModel}
  */
 WebInspector.console;