Do not make a subclass of Text only to disable selection.

Source/core/dom/Text.h

Index: Source/core/dom/Text.h
diff --git a/Source/core/dom/Text.h b/Source/core/dom/Text.h
index 603a018394c780d18e790f3c6edc90239cf52947..79540c0b3992185040a168cdc209934aab824ba6 100644
--- a/Source/core/dom/Text.h
+++ b/Source/core/dom/Text.h
@@ -50,7 +50,7 @@ public:
 
     void recalcTextStyle(StyleRecalcChange, Text* nextTextSibling);
     bool textRendererIsNeeded(const NodeRenderingContext&);
-    virtual RenderText* createTextRenderer(RenderStyle*);
+    RenderText* createTextRenderer(RenderStyle*);
     void updateTextRenderer(unsigned offsetOfReplacedData, unsigned lengthOfReplacedData, RecalcStyleBehavior = DoNotRecalcStyle);
 
     virtual void attach(const AttachContext& = AttachContext()) OVERRIDE FINAL;