Revert "Change isBlock and isInline functions to check for isElementNode"

Source/core/editing/htmlediting.cpp

Index: Source/core/editing/htmlediting.cpp
diff --git a/Source/core/editing/htmlediting.cpp b/Source/core/editing/htmlediting.cpp
index 7d8591fc4ea59d4a734b0ca6a11b29a6f767a64a..11295afa05ba1a8866a0b4a5b4893a28398fd901 100644
--- a/Source/core/editing/htmlediting.cpp
+++ b/Source/core/editing/htmlediting.cpp
@@ -309,12 +309,12 @@ VisiblePosition lastEditablePositionBeforePositionInRoot(const Position& positio
 // Whether or not content before and after this node will collapse onto the same line as it.
 bool isBlock(const Node* node)
 {
-    return node && node->isElementNode() && node->renderer() && !node->renderer()->isInline() && !node->renderer()->isRubyText();
+    return node && node->renderer() && !node->renderer()->isInline() && !node->renderer()->isRubyText();
 }
 
 bool isInline(const Node* node)
 {
-    return node && node->isElementNode() && node->renderer() && node->renderer()->isInline();
+    return node && node->renderer() && node->renderer()->isInline();
 }
 
 // FIXME: Deploy this in all of the places where enclosingBlockFlow/enclosingBlockFlowOrTableElement are used.
@@ -324,7 +324,7 @@ bool isInline(const Node* node)
 Element* enclosingBlock(Node* node, EditingBoundaryCrossingRule rule)
 {
     Node* enclosingNode = enclosingNodeOfType(firstPositionInOrBeforeNode(node), isBlock, rule);
-    return toElement(enclosingNode);
+    return enclosingNode && enclosingNode->isElementNode() ? toElement(enclosingNode) : 0;
 }
 
 TextDirection directionOfEnclosingBlock(const Position& position)