Accessible setSelection function should use VisiblePositions

third_party/WebKit/Source/modules/accessibility/AXLayoutObject.cpp

Index: third_party/WebKit/Source/modules/accessibility/AXLayoutObject.cpp
diff --git a/third_party/WebKit/Source/modules/accessibility/AXLayoutObject.cpp b/third_party/WebKit/Source/modules/accessibility/AXLayoutObject.cpp
index c780186a855528cd7f12301a390698cbf61c3ff1..0a92208d5194a59991460ecdf23dc3bd731eaf3b 100644
--- a/third_party/WebKit/Source/modules/accessibility/AXLayoutObject.cpp
+++ b/third_party/WebKit/Source/modules/accessibility/AXLayoutObject.cpp
@@ -1940,9 +1940,15 @@ void AXLayoutObject::setSelection(const AXRange& selection)
     if (!frame)
         return;
 
-    frame->selection().setSelection(VisibleSelection(
-        Position(anchorNode, selection.anchorOffset),
-        Position(focusNode, selection.focusOffset)));
+    // Set the selection based on visible positions, because the offsets in accessibility nodes
+    // are based on visible indexes, which often skips redundant whitespace, for example.
+    ContainerNode* anchorContainerNode = anchorNode->isContainerNode() ? toContainerNode(anchorNode) : anchorNode->parentNode();
+    ContainerNode* focusContainerNode = focusNode->isContainerNode() ? toContainerNode(focusNode) : focusNode->parentNode();
+    if (anchorContainerNode && focusContainerNode) {
+        VisiblePosition anchorVisiblePosition = blink::visiblePositionForIndex(selection.anchorOffset, anchorContainerNode);
+        VisiblePosition focusVisiblePosition = blink::visiblePositionForIndex(selection.focusOffset, focusContainerNode);
+        frame->selection().setSelection(VisibleSelection(anchorVisiblePosition, focusVisiblePosition));
+    }
 }
 
 bool AXLayoutObject::isValidSelectionBound(const AXObject* boundObject) const