Fixed AXLayoutObject::getSelection() so that it doesn't return nullptr for anchor and focus objects.

Source/modules/accessibility/AXLayoutObject.cpp

 /*
 * Copyright (C) 2008 Apple 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
@@ skipping 1847 matching lines @@
     int focusOffset = selectionRange->endOffset();
     ASSERT(focusOffset >= 0);
 
     Node* anchorNode = selectionRange->startContainer();
     ASSERT(anchorNode);
 
     RefPtrWillBeRawPtr<AXObject> anchorObject = nullptr;
     // Find the closest node that has a corresponding AXObject.
     // This is because some nodes may be aria hidden or might not even have
     // a layout object if they are part of the shadow DOM.
-    while (anchorNode && !getUnignoredObjectFromNode(*anchorNode)) {
+    while (anchorNode
+        && !(anchorObject = getUnignoredObjectFromNode(*anchorNode))) {
         if (anchorNode->nextSibling())
             anchorNode = anchorNode->nextSibling();
         else
             anchorNode = anchorNode->parentNode();
     }
     if (anchorNode != selectionRange->startContainer())
         anchorOffset = 0;
 
     Node* focusNode = selectionRange->endContainer();
     ASSERT(focusNode);
 
     RefPtrWillBeRawPtr<AXObject> focusObject = nullptr;
-    while (focusNode && !getUnignoredObjectFromNode(*focusNode)) {
+    while (focusNode
+        && !(focusObject = getUnignoredObjectFromNode(*focusNode))) {
         if (focusNode->previousSibling())
             focusNode = focusNode->previousSibling();
         else
             focusNode = focusNode->parentNode();
     }
     if (focusNode != selectionRange->endContainer())
         focusOffset = 0;
 
     if (!anchorObject || !focusObject)
         return AXRange();
@@ skipping 753 matching lines @@
         if (label && label->layoutObject()) {
             LayoutRect labelRect = axObjectCache().getOrCreate(label)->elementRect();
             result.unite(labelRect);
         }
     }
 
     return result;
 }
 
 } // namespace blink