Optimize / clean up hasTagName() call sites

Source/core/editing/ReplaceSelectionCommand.cpp

 /*
  * Copyright (C) 2005, 2006, 2008 Apple Inc. All rights reserved.
  * Copyright (C) 2009, 2010, 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 419 matching lines @@
 static bool isMailPasteAsQuotationNode(const Node* node)
 {
     if (!node || !node->hasTagName(blockquoteTag) || toElement(node)->getAttribute(classAttr) != ApplePasteAsQuotation)
         return false;
     UseCounter::count(node->document(), UseCounter::EditingApplePasteAsQuotation);
     return true;
 }
 
 static bool isHeaderElement(const Node* a)
 {
-    if (!a)
+    if (!a || !a->isHTMLElement())
         return false;
 
-    return a->hasTagName(h1Tag)
-        || a->hasTagName(h2Tag)
-        || a->hasTagName(h3Tag)
-        || a->hasTagName(h4Tag)
-        || a->hasTagName(h5Tag)
-        || a->hasTagName(h6Tag);
+    const HTMLElement& element = toHTMLElement(*a);
+    return element.hasTagName(h1Tag)
+        || element.hasTagName(h2Tag)
+        || element.hasTagName(h3Tag)
+        || element.hasTagName(h4Tag)
+        || element.hasTagName(h5Tag)
+        || element.hasTagName(h6Tag);
 }
 
 static bool haveSameTagName(Node* a, Node* b)
 {
     return a && b && a->isElementNode() && b->isElementNode() && toElement(a)->tagName() == toElement(b)->tagName();
 }
 
 bool ReplaceSelectionCommand::shouldMerge(const VisiblePosition& source, const VisiblePosition& destination)
 {
     if (source.isNull() || destination.isNull())
         return false;
 
     Node* sourceNode = source.deepEquivalent().deprecatedNode();
     Node* destinationNode = destination.deepEquivalent().deprecatedNode();
-    Node* sourceBlock = enclosingBlock(sourceNode);
-    Node* destinationBlock = enclosingBlock(destinationNode);
+    Element* sourceBlock = enclosingBlock(sourceNode);
+    Element* destinationBlock = enclosingBlock(destinationNode);
     return !enclosingNodeOfType(source.deepEquivalent(), &isMailPasteAsQuotationNode) &&
            sourceBlock && (!sourceBlock->hasTagName(blockquoteTag) || isMailBlockquote(sourceBlock))  &&
            enclosingListChild(sourceBlock) == enclosingListChild(destinationNode) &&
            enclosingTableCell(source.deepEquivalent()) == enclosingTableCell(destination.deepEquivalent()) &&
            (!isHeaderElement(sourceBlock) || haveSameTagName(sourceBlock, destinationBlock)) &&
            // Don't merge to or from a position before or after a block because it would
            // be a no-op and cause infinite recursion.
            !isBlock(sourceNode) && !isBlock(destinationNode);
 }
 
@@ skipping 1053 matching lines @@
 void ReplaceSelectionCommand::trace(Visitor* visitor)
 {
     visitor->trace(m_startOfInsertedContent);
     visitor->trace(m_endOfInsertedContent);
     visitor->trace(m_insertionStyle);
     visitor->trace(m_documentFragment);
     CompositeEditCommand::trace(visitor);
 }
 
 } // namespace blink