Use tighter typing in editing: SimplifyMarkupCommand & TextIterator

Source/core/editing/TextIterator.h

Index: Source/core/editing/TextIterator.h
diff --git a/Source/core/editing/TextIterator.h b/Source/core/editing/TextIterator.h
index cae9dc5abcfeb684700a3c9690f8d7aa3e23d726..6693bd4b9e35e1602e48fb31c9e1ee68e3007aa3 100644
--- a/Source/core/editing/TextIterator.h
+++ b/Source/core/editing/TextIterator.h
@@ -142,8 +142,7 @@ private:
     void handleTextNodeFirstLetter(RenderTextFragment*);
     bool hasVisibleTextNode(RenderText*);
     void emitCharacter(UChar, Node* textNode, Node* offsetBaseNode, int textStartOffset, int textEndOffset);
-    void emitText(Node* textNode, RenderObject* renderObject, int textStartOffset, int textEndOffset);
-    void emitText(Node* textNode, int textStartOffset, int textEndOffset);
+    void emitText(Node* textNode, RenderText* renderer, int textStartOffset, int textEndOffset);
 
     // Current position, not necessarily of the text being returned, but position
     // as we walk through the DOM tree.
@@ -179,7 +178,7 @@ private:
     RenderText *m_firstLetterText;
 
     // Used to do the whitespace collapsing logic.
-    RawPtrWillBeMember<Node> m_lastTextNode;
+    RawPtrWillBeMember<Text> m_lastTextNode;
     bool m_lastTextNodeEndedWithCollapsedSpace;
     UChar m_lastCharacter;
 
@@ -281,7 +280,7 @@ private:
     int m_textLength;
 
     // Used to do the whitespace logic.
-    RawPtrWillBeMember<Node> m_lastTextNode;
+    RawPtrWillBeMember<Text> m_lastTextNode;
     UChar m_lastCharacter;
 
     // Used for whitespace characters that aren't in the DOM, so we can point at them.