Introduce DEFINE_RENDER_OBJECT_TYPE_CASTS to replace manual toRenderFoo, and use it

Source/core/rendering/RenderText.h

Index: Source/core/rendering/RenderText.h
diff --git a/Source/core/rendering/RenderText.h b/Source/core/rendering/RenderText.h
index cd2732e3303f9a7de79550a9fcd7f49148ee0ee8..b797a422cbce1fe72f5a92c3b3cb5203067c4638 100644
--- a/Source/core/rendering/RenderText.h
+++ b/Source/core/rendering/RenderText.h
@@ -224,20 +224,7 @@ inline UChar RenderText::characterAt(unsigned i) const
     return uncheckedCharacterAt(i);
 }
 
-inline RenderText* toRenderText(RenderObject* object)
-{
-    ASSERT_WITH_SECURITY_IMPLICATION(!object || object->isText());
-    return static_cast<RenderText*>(object);
-}
-
-inline const RenderText* toRenderText(const RenderObject* object)
-{
-    ASSERT_WITH_SECURITY_IMPLICATION(!object || object->isText());
-    return static_cast<const RenderText*>(object);
-}
-
-// This will catch anyone doing an unnecessary cast.
-void toRenderText(const RenderText*);
+DEFINE_RENDER_OBJECT_TYPE_CASTS(RenderText, isText());
 
 #ifdef NDEBUG
 inline void RenderText::checkConsistency() const