Use tighter typing in editing: BreakBlockquoteCommand & Caret

Source/core/editing/FrameSelection.cpp

Index: Source/core/editing/FrameSelection.cpp
diff --git a/Source/core/editing/FrameSelection.cpp b/Source/core/editing/FrameSelection.cpp
index 7301e5ff67b7d9e8111f4aac4ccdbd0775a7b577..25f461116beee88e082c3bb83b2d6873608e00d6 100644
--- a/Source/core/editing/FrameSelection.cpp
+++ b/Source/core/editing/FrameSelection.cpp
@@ -1212,7 +1212,7 @@ void FrameSelection::setExtent(const VisiblePosition &pos, EUserTriggered userTr
     setSelection(VisibleSelection(m_selection.base(), pos.deepEquivalent(), pos.affinity(), selectionHasDirection), CloseTyping | ClearTypingStyle | userTriggered);
 }
 
-RenderObject* FrameSelection::caretRenderer() const
+RenderBlock* FrameSelection::caretRenderer() const
 {
     return CaretBase::caretRenderer(m_selection.start().deprecatedNode());
 }