Revert 151179 "On IE and FireFox, they treats contenteditable="f..."

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 80b36f7907437d16ed7d4670f9045e16c9320942..69a59f3064ddfba20a4b7531e0de1a07c4889e9d 100644
--- a/Source/core/editing/htmlediting.cpp
+++ b/Source/core/editing/htmlediting.cpp
@@ -66,18 +66,7 @@ using namespace HTMLNames;
 // purposes of editing.
 bool isAtomicNode(const Node *node)
 {
-    if (!node)
-        return false;
-    if (!node->hasChildNodes() || editingIgnoresContent(node))
-        return true;
-    RenderObject* renderer = node->renderer();
-    if (!renderer)
-        return false;
-    // For compatibility with IE, we allow to move caret into table cell event
-    // if TABLE and TR are uneditable.
-    if (renderer->isTable() || renderer->isTableRow())
-        return false;
-    return renderer->style()->userModify() == READ_ONLY && lowestEditableAncestor(node);
+    return node && (!node->hasChildNodes() || editingIgnoresContent(node));
 }
 
 // Compare two positions, taking into account the possibility that one or both
@@ -139,7 +128,7 @@ Node* highestEditableRoot(const Position& position, EditableType editableType)
     return highestRoot;
 }
 
-Node* lowestEditableAncestor(const Node* node)
+Node* lowestEditableAncestor(Node* node)
 {
     if (!node)
         return 0;