Introduce VisiblePosition::isValid

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 161 matching lines @@
 void FrameSelection::moveTo(const Position &pos, TextAffinity affinity)
 {
     SetSelectionOptions options = CloseTyping | ClearTypingStyle;
     setSelection(VisibleSelection(pos, affinity, selection().isDirectional()), options);
 }
 
 // TODO(xiaochengh): We should not use reference to return value.
 template <typename Strategy>
 static void adjustEndpointsAtBidiBoundary(VisiblePositionTemplate<Strategy>& visibleBase, VisiblePositionTemplate<Strategy>& visibleExtent)
 {
-    // TODO(xiaochengh): Replace it with |DCHECK(visibleBase.isValid())| and
-    // |DCHECK(visibleExtent.isValid())| once |VisiblePosition::isValid| is
-    // implemented.
-    DCHECK(visibleBase.isNull() || !visibleBase.deepEquivalent().document()->needsLayoutTreeUpdate());
+    DCHECK(visibleBase.isValid());
+    DCHECK(visibleExtent.isValid());
 
     RenderedPosition base(visibleBase);
     RenderedPosition extent(visibleExtent);
 
     if (base.isNull() || extent.isNull() || base.isEquivalent(extent))
         return;
 
     if (base.atLeftBoundaryOfBidiRun()) {
         if (!extent.atRightBoundaryOfBidiRun(base.bidiLevelOnRight())
             && base.isEquivalent(extent.leftBoundaryOfBidiRun(base.bidiLevelOnRight()))) {
@@ skipping 1198 matching lines @@
 
 void showTree(const blink::FrameSelection* sel)
 {
     if (sel)
         sel->showTreeForThis();
     else
         LOG(INFO) << "Cannot showTree for <null> FrameSelection.";
 }
 
 #endif