DCHECK instead of return at LayoutSelection::Commit()

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

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights
  * reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 314 matching lines @@
   // necessarily valid, and the following steps assume a valid selection. See
   // <https://bugs.webkit.org/show_bug.cgi?id=69563> and
   // <rdar://problem/10232866>.
   const VisibleSelectionInFlatTree& selection =
       CreateVisibleSelection(CalcVisibleSelection(original_selection));
 
   if (!selection.IsRange() || frame_selection_->IsHidden()) {
     ClearSelection();
     return;
   }
-
+  DCHECK(!selection.IsNone());
   // Use the rightmost candidate for the start of the selection, and the
   // leftmost candidate for the end of the selection. Example: foo <a>bar</a>.
   // Imagine that a line wrap occurs after 'foo', and that 'bar' is selected.
   // If we pass [foo, 3] as the start of the selection, the selection painting
   // code will think that content on the line containing 'foo' is selected
   // and will fill the gap before 'bar'.
   PositionInFlatTree start_pos = selection.Start();
-  PositionInFlatTree candidate = MostForwardCaretPosition(start_pos);
-  if (IsVisuallyEquivalentCandidate(candidate))
-    start_pos = candidate;
+  const PositionInFlatTree most_forward_start =
+      MostForwardCaretPosition(start_pos);
+  if (IsVisuallyEquivalentCandidate(most_forward_start))
+    start_pos = most_forward_start;
   PositionInFlatTree end_pos = selection.end();
-  candidate = MostBackwardCaretPosition(end_pos);
-  if (IsVisuallyEquivalentCandidate(candidate))
-    end_pos = candidate;
+  const PositionInFlatTree most_backward = MostBackwardCaretPosition(end_pos);
+  if (IsVisuallyEquivalentCandidate(most_backward))
+    end_pos = most_backward;
 
-  // We can get into a state where the selection endpoints map to the same
-  // |VisiblePosition| when a selection is deleted because we don't yet notify
-  // the |FrameSelection| of text removal.
-  if (start_pos.IsNull() || end_pos.IsNull() ||
-      selection.VisibleStart().DeepEquivalent() ==
-          selection.VisibleEnd().DeepEquivalent())
-    return;
+  DCHECK(start_pos.IsNotNull());
+  DCHECK(end_pos.IsNotNull());
   DCHECK_LE(start_pos, end_pos);
   LayoutObject* start_layout_object = start_pos.AnchorNode()->GetLayoutObject();
   LayoutObject* end_layout_object = end_pos.AnchorNode()->GetLayoutObject();
-  if (!start_layout_object || !end_layout_object)
-    return;
+  DCHECK(start_layout_object);
+  DCHECK(end_layout_object);
   DCHECK(start_layout_object->View() == end_layout_object->View());
 
   const SelectionPaintRange new_range(
       start_layout_object, start_pos.ComputeEditingOffset(), end_layout_object,
       end_pos.ComputeEditingOffset());
   // Just return if the selection hasn't changed.
   if (paint_range_ == new_range)
     return;
 
   DCHECK(frame_selection_->GetDocument().GetLayoutView()->GetFrameView());
@@ skipping 71 matching lines @@
 
     o->SetShouldInvalidateSelection();
   }
 }
 
 DEFINE_TRACE(LayoutSelection) {
   visitor->Trace(frame_selection_);
 }
 
 }  // namespace blink