Change deleteCell behavior when there are no cells

third_party/WebKit/Source/core/html/HTMLTableRowElement.cpp

 /*
  * Copyright (C) 1997 Martin Jones (mjones@kde.org)
  *           (C) 1997 Torben Weis (weis@kde.org)
  *           (C) 1998 Waldo Bastian (bastian@kde.org)
  *           (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2010 Apple Inc. All rights
  * reserved.
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 96 matching lines @@
     appendChild(cell, exceptionState);
   else
     insertBefore(cell, children->item(index), exceptionState);
   return cell;
 }
 
 void HTMLTableRowElement::deleteCell(int index,
                                      ExceptionState& exceptionState) {
   HTMLCollection* children = cells();
   int numCells = children ? children->length() : 0;
-  if (index == -1)
-    index = numCells - 1;
-  if (index >= 0 && index < numCells) {
-    Element* cell = children->item(index);
-    HTMLElement::removeChild(cell, exceptionState);
-  } else {
+  // 1. If index is less than −1 or greater than the number of
+  // elements in the cells collection, then throw "IndexSizeError".

[foolip, 2016/10/12 14:19:01]

Oh look, the spec has a bug here, doesn't it? I couldn't find you on GitHub, if
you have an account can you review https://github.com/whatwg/html/pull/1890?

This comment needs to be updated to match, too.

[rwlbuis, 2016/10/12 15:29:39]

I added myself and okayed the change.
Done :)

+  if (index < -1 || index >= numCells) {
     exceptionState.throwDOMException(
         IndexSizeError, "The value provided (" + String::number(index) +
                             ") is outside the range [0, " +
                             String::number(numCells) + ").");
+    return;
   }
+  // 2. If index is −1, remove the last element in the cells collection
+  // from its parent, or do nothing if the cells collection is empty.
+  if (index == -1) {
+    if (numCells == 0)
+      return;
+    index = numCells - 1;
+  }
+  // 3. Remove the indexth element in the cells collection from its parent.
+  Element* cell = children->item(index);
+  HTMLElement::removeChild(cell, exceptionState);
 }
 
 HTMLCollection* HTMLTableRowElement::cells() {
   return ensureCachedCollection<HTMLCollection>(TRCells);
 }
 
 }  // namespace blink