Make FrameSelection::create() to take LocalFrame as required parameter

third_party/WebKit/Source/core/editing/FrameSelection.cpp

 /*
  * Copyright (C) 2004, 2008, 2009, 2010 Apple 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 89 matching lines @@
     , m_xPosForVerticalArrowNavigation(NoXPosForVerticalArrowNavigation())
     , m_previousCaretVisibility(CaretVisibility::Hidden)
     , m_caretBlinkTimer(this, &FrameSelection::caretBlinkTimerFired)
     , m_caretRectDirty(true)
     , m_shouldPaintCaret(true)
     , m_isCaretBlinkingSuspended(false)
     , m_focused(frame && frame->page() && frame->page()->focusController().focusedFrame() == frame)
     , m_shouldShowBlockCursor(false)
     , m_caretBase(adoptPtr(new CaretBase))
 {
+    // TODO(yosin): We should remove null check for |m_frame| in
+    // "FrameSelection.cpp", since it never be null.
+    DCHECK(frame);
     if (shouldAlwaysUseDirectionalSelection(m_frame))
         m_selectionEditor->setIsDirectional(true);
 }
 
 FrameSelection::~FrameSelection()
 {
 }
 
 template <>
 VisiblePosition FrameSelection::originalBase<EditingStrategy>() const
@@ skipping 1325 matching lines @@
 
 void showTree(const blink::FrameSelection* sel)
 {
     if (sel)
         sel->showTreeForThis();
     else
         fprintf(stderr, "Cannot showTree for (nil) FrameSelection.\n");
 }
 
 #endif