Minimize RenderObject* casting to RenderText*

Source/core/editing/InsertLineBreakCommand.cpp

 /*
  * Copyright (C) 2005, 2006 Apple Computer, Inc.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 20 matching lines @@
 #include "core/dom/Text.h"
 #include "core/editing/EditingStyle.h"
 #include "core/editing/FrameSelection.h"
 #include "core/editing/VisiblePosition.h"
 #include "core/editing/VisibleUnits.h"
 #include "core/editing/htmlediting.h"
 #include "core/frame/LocalFrame.h"
 #include "core/html/HTMLBRElement.h"
 #include "core/html/HTMLElement.h"
 #include "core/rendering/RenderObject.h"
+#include "core/rendering/RenderText.h"
 
 namespace blink {
 
 using namespace HTMLNames;
 
 InsertLineBreakCommand::InsertLineBreakCommand(Document& document)
     : CompositeEditCommand(document)
 {
 }
 
@@ skipping 105 matching lines @@
         // before the line break (if the line break is at the end of a block it isn't selectable).
         // So, this next call sets the endingSelection() to a caret just after the line break
         // that we inserted, or just before it if it's at the end of a block.
         setEndingSelection(endingSelection().visibleEnd());
     }
 
     rebalanceWhitespace();
 }
 
 }