Make VisibleSelection::setWithoutValidation() to handle TextAffinity::Upstream

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

 /*
  * Copyright (C) 2004, 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 637 matching lines @@
 // manipulate selections that are not currently valid.
 template <typename Strategy>
 void VisibleSelectionTemplate<Strategy>::setWithoutValidation(const PositionTemplate<Strategy>& base, const PositionTemplate<Strategy>& extent)
 {
     if (base.isNull() || extent.isNull()) {
         m_base = m_extent = m_start = m_end = PositionTemplate<Strategy>();
         updateSelectionType();
         return;
     }
 
-    // TODO(hajimehoshi): We doubt this assertion is needed. This was introduced
-    // by http://trac.webkit.org/browser/trunk/WebCore/editing/Selection.cpp?annotate=blame&rev=21071
-    ASSERT(m_affinity == TextAffinity::Downstream);
-
     m_base = base;
     m_extent = extent;
     m_baseIsFirst = base.compareTo(extent) <= 0;
     if (m_baseIsFirst) {
         m_start = base;
         m_end = extent;
     } else {
         m_start = extent;
         m_end = base;
     }
     m_selectionType = base == extent ? CaretSelection : RangeSelection;
+    if (m_selectionType != CaretSelection) {
+        // Since |m_affinity| for non-|CaretSelection| is always |Downstream|,
+        // we should keep this invariant. Note: This function can be called with
+        // |m_affinity| is |TextAffinity::Upstream|.
+        m_affinity = TextAffinity::Downstream;
+    }
     didChange();
 }
 
 static PositionInComposedTree adjustPositionInComposedTreeForStart(const PositionInComposedTree& position, Node* shadowHost)
 {
     if (isEnclosedBy(position, *shadowHost)) {
         if (position.isBeforeChildren())
             return PositionInComposedTree::beforeNode(shadowHost);
         return PositionInComposedTree::afterNode(shadowHost);
     }
@@ skipping 452 matching lines @@
 {
     sel.showTreeForThis();
 }
 
 void showTree(const blink::VisibleSelectionInComposedTree* sel)
 {
     if (sel)
         sel->showTreeForThis();
 }
 #endif