Do not send redundant selectionchange-events (decouple focus)

third_party/WebKit/Source/core/editing/PendingSelection.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 105 matching lines @@
       m_frameSelection->computeVisibleSelectionInFlatTree();
 
   // Skip if pending VisibilePositions became invalid before we reach here.
   if (!isSelectionInDocument(originalSelection, layoutView.document()))
     return;
 
   // Construct a new VisibleSolution, since visibleSelection() is not
   // 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(originalSelection));
+  const SelectionInFlatTree selection = calcVisibleSelection(originalSelection);
+  const VisibleSelectionInFlatTree& visibleSelection =
+      createVisibleSelection(selection);
 
-  if (!selection.isRange()) {
+  if (!visibleSelection.isRange() || !selectionHasFocus(selection)) {
     layoutView.clearSelection();
     return;
   }
 
   // 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 startPos = selection.start();
+  PositionInFlatTree startPos = visibleSelection.start();
   PositionInFlatTree candidate = mostForwardCaretPosition(startPos);
   if (isVisuallyEquivalentCandidate(candidate))
     startPos = candidate;
-  PositionInFlatTree endPos = selection.end();
+  PositionInFlatTree endPos = visibleSelection.end();
   candidate = mostBackwardCaretPosition(endPos);
   if (isVisuallyEquivalentCandidate(candidate))
     endPos = candidate;
 
   // 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 (startPos.isNull() || endPos.isNull() ||
-      selection.visibleStart().deepEquivalent() ==
-          selection.visibleEnd().deepEquivalent())
+      visibleSelection.visibleStart().deepEquivalent() ==
+          visibleSelection.visibleEnd().deepEquivalent())
     return;
   LayoutObject* startLayoutObject = startPos.anchorNode()->layoutObject();
   LayoutObject* endLayoutObject = endPos.anchorNode()->layoutObject();
   if (!startLayoutObject || !endLayoutObject)
     return;
   DCHECK(layoutView == startLayoutObject->view());
   DCHECK(layoutView == endLayoutObject->view());
   layoutView.setSelection(startLayoutObject, startPos.computeEditingOffset(),
                           endLayoutObject, endPos.computeEditingOffset());
 }
 
 DEFINE_TRACE(PendingSelection) {
   visitor->trace(m_frameSelection);
 }
 
 }  // namespace blink