Enable strict type checking for Selection.selectAllChildren()

Source/core/editing/Selection.idl

 /*
  * Copyright (C) 2007 Apple Inc.  All rights reserved.
  * Copyright (C) 2009 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:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
@@ skipping 35 matching lines @@
 
     readonly attribute boolean isCollapsed;
     [RaisesException] void collapse(Node? node, optional long offset = 0);
     [RaisesException] void collapseToStart();
     [RaisesException] void collapseToEnd();
 
     // We mark offset as optional, defaulting to 0; this differs from spec.
     // http://crbug.com/384966
     [RaisesException, TypeChecking=Interface] void extend(Node node, optional long offset = 0);
 
-    [RaisesException] void selectAllChildren(Node node);
+    [RaisesException, TypeChecking=Interface] void selectAllChildren(Node node);
     [CustomElementCallbacks] void deleteFromDocument();
 
     readonly attribute long rangeCount;
     [RaisesException] Range getRangeAt(long index);
     void addRange(Range range);
     void removeAllRanges();
 
     [NotEnumerable] stringifier;
 
     // Firefox extensions
@@ skipping 17 matching lines @@
     [MeasureAs=SelectionSetBaseAndExtent, RaisesException] void setBaseAndExtent([Default=Undefined] optional Node baseNode,
                                                                                  [Default=Undefined] optional long baseOffset,
                                                                                  [Default=Undefined] optional Node extentNode,
                                                                                  [Default=Undefined] optional long extentOffset);
     [ImplementedAs=collapse, MeasureAs=SelectionSetPosition, RaisesException] void setPosition(Node? node, optional long offset = 0);
 
     // IE extensions
     // http://msdn.microsoft.com/en-us/library/ms535869(VS.85).aspx
     [MeasureAs=SelectionEmpty] void empty();
 };