Introduce isHTMLTableElement and toHTMLTableElement

Source/core/editing/DeleteSelectionCommand.cpp

Index: Source/core/editing/DeleteSelectionCommand.cpp
diff --git a/Source/core/editing/DeleteSelectionCommand.cpp b/Source/core/editing/DeleteSelectionCommand.cpp
index a01bb00bf2e032a4263dba30772596db6beafcec..9ba5478843d829c558f1d7882ba0384f3f6fa488 100644
--- a/Source/core/editing/DeleteSelectionCommand.cpp
+++ b/Source/core/editing/DeleteSelectionCommand.cpp
@@ -36,6 +36,7 @@
 #include "core/editing/VisibleUnits.h"
 #include "core/editing/htmlediting.h"
 #include "core/html/HTMLInputElement.h"
+#include "core/html/HTMLTableElement.h"
 #include "core/page/Frame.h"
 #include "core/rendering/RenderTableCell.h"
 
@@ -443,7 +444,7 @@ void DeleteSelectionCommand::handleGeneralDelete()
     makeStylingElementsDirectChildrenOfEditableRootToPreventStyleLoss();
 
     // Never remove the start block unless it's a table, in which case we won't merge content in.
-    if (startNode == m_startBlock && startOffset == 0 && canHaveChildrenForEditing(startNode) && !startNode->hasTagName(tableTag)) {
+    if (startNode->isSameNode(m_startBlock.get()) && !startOffset && canHaveChildrenForEditing(startNode) && !isHTMLTableElement(startNode)) {
         startOffset = 0;
         startNode = NodeTraversal::next(startNode);
         if (!startNode)