[Editing][Regression] Contenteditable w/ "-webkit-user-select:all" should be editable.

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

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2012 Digia Plc. and/or its subsidiary(-ies)
  * Copyright (C) 2015 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:
  * 1. Redistributions of source code must retain the above copyright
@@ skipping 69 matching lines @@
         return DispatchEventResult::NotCanceled;
 
     return node->dispatchEvent(Event::createCancelableBubble(EventTypeNames::selectstart));
 }
 
 VisibleSelectionInFlatTree expandSelectionToRespectUserSelectAll(Node* targetNode, const VisibleSelectionInFlatTree& selection)
 {
     Node* rootUserSelectAll = EditingInFlatTreeStrategy::rootUserSelectAllForNode(targetNode);
     if (!rootUserSelectAll)
         return selection;
+    if (rootUserSelectAll->isHTMLElement() && toHTMLElement(rootUserSelectAll)->isTextFormControl())
+        return selection;
+    if (rootUserSelectAll->layoutObject()->style()->userModify() != READ_ONLY)
+        return selection;
 
     VisibleSelectionInFlatTree newSelection(selection);
     newSelection.setBase(mostBackwardCaretPosition(PositionInFlatTree::beforeNode(rootUserSelectAll), CanCrossEditingBoundary));
     newSelection.setExtent(mostForwardCaretPosition(PositionInFlatTree::afterNode(rootUserSelectAll), CanCrossEditingBoundary));
 
     return newSelection;
 }
 
 static int textDistance(const PositionInFlatTree& start, const PositionInFlatTree& end)
 {
@@ skipping 570 matching lines @@
     return event.event().altKey() && event.isOverLink();
 }
 
 bool isExtendingSelection(const MouseEventWithHitTestResults& event)
 {
     bool isMouseDownOnLinkOrImage = event.isOverLink() || event.hitTestResult().image();
     return event.event().shiftKey() && !isMouseDownOnLinkOrImage;
 }
 
 } // namespace blink