Use tighter typing in editing: BreakBlockquoteCommand & Caret

Source/core/editing/Caret.h

Index: Source/core/editing/Caret.h
diff --git a/Source/core/editing/Caret.h b/Source/core/editing/Caret.h
index b0d3eb95a412521c043cdff37ce253f5fd1869d6..34febde4c89cd0703561c6358c5baa17fb418003 100644
--- a/Source/core/editing/Caret.h
+++ b/Source/core/editing/Caret.h
@@ -35,7 +35,7 @@ namespace blink {
 
 class LocalFrame;
 class GraphicsContext;
-class RenderObject;
+class RenderBlock;
 class RenderView;
 
 class CaretBase {
@@ -62,7 +62,7 @@ protected:
     CaretVisibility caretVisibility() const { return m_caretVisibility; }
 
 protected:
-    static RenderObject* caretRenderer(Node*);
+    static RenderBlock* caretRenderer(Node*);
     static void repaintCaretForLocalRect(Node*, const LayoutRect&);
 
 private:
@@ -77,7 +77,7 @@ class DragCaretController FINAL : public NoBaseWillBeGarbageCollected<DragCaretC
 public:
     static PassOwnPtrWillBeRawPtr<DragCaretController> create();
 
-    RenderObject* caretRenderer() const;
+    RenderBlock* caretRenderer() const;
     void paintDragCaret(LocalFrame*, GraphicsContext*, const LayoutPoint&, const LayoutRect& clipRect) const;
 
     bool isContentEditable() const { return m_position.rootEditableElement(); }