Revert of Remove ClearSelection() from Layout{BlockFlow,Inline}::WillbeDestroyed()

third_party/WebKit/Source/core/layout/LayoutBlockFlow.cpp

 /*
  * Copyright (C) 2013 Google 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 2809 matching lines @@
   LayoutBoxModelObject* continuation = this->Continuation();
   if (continuation) {
     continuation->Destroy();
     SetContinuation(nullptr);
   }
 
   if (!DocumentBeingDestroyed()) {
     // TODO(mstensho): figure out if we need this. We have no test coverage for
     // it. It looks like all line boxes have been removed at this point.
     if (FirstLineBox()) {
+      // We can't wait for LayoutBox::destroy to clear the selection,
+      // because by then we will have nuked the line boxes.
+      // FIXME: The FrameSelection should be responsible for this when it
+      // is notified of DOM mutations.
+      if (IsSelectionBorder())
+        View()->ClearSelection();
+
       // If we are an anonymous block, then our line boxes might have children
       // that will outlast this block. In the non-anonymous block case those
       // children will be destroyed by the time we return from this function.
       if (IsAnonymousBlock()) {
         for (InlineFlowBox* box = FirstLineBox(); box;
              box = box->NextLineBox()) {
           while (InlineBox* child_box = box->FirstChild())
             child_box->Remove();
         }
       }
@@ skipping 1815 matching lines @@
   return LayoutBlock::InvalidatePaintIfNeeded(paint_invalidation_state);
 }
 
 void LayoutBlockFlow::InvalidateDisplayItemClients(
     PaintInvalidationReason invalidation_reason) const {
   BlockFlowPaintInvalidator(*this).InvalidateDisplayItemClients(
       invalidation_reason);
 }
 
 }  // namespace blink