Use text affinity to return correct accessible line boundaries.

third_party/WebKit/Source/modules/accessibility/AXObject.h

 /*
  * Copyright (C) 2008, 2009, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Nuanti Ltd.
  *
  * 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.
@@ skipping 475 matching lines @@
     typedef HeapVector<Member<AXObject>> AXObjectVector;
 
     struct AXRange {
         DISALLOW_NEW_EXCEPT_PLACEMENT_NEW();
         // The deepest descendant in which the range starts.
         // (nullptr means the current object.)
         Persistent<AXObject> anchorObject;
         // The number of characters and child objects in the anchor object
         // before the range starts.
         int anchorOffset;
+        // When the same character offset could correspond to two possible
+        // cursor positions, upstream means it's on the previous line rather
+        // than the next line.
+        TextAffinity anchorAffinity;
+
         // The deepest descendant in which the range ends.
         // (nullptr means the current object.)
         Persistent<AXObject> focusObject;
         // The number of characters and child objects in the focus object
         // before the range ends.
         int focusOffset;
+        // When the same character offset could correspond to two possible
+        // cursor positions, upstream means it's on the previous line rather
+        // than the next line.
+        TextAffinity focusAffinity;
 
         AXRange()
             : anchorObject(nullptr)
             , anchorOffset(-1)
+            , anchorAffinity(TextAffinity::Upstream)
             , focusObject(nullptr)
             , focusOffset(-1)
+            , focusAffinity(TextAffinity::Downstream)
         { }
 
         AXRange(int startOffset, int endOffset)
             : anchorObject(nullptr)
             , anchorOffset(startOffset)
+            , anchorAffinity(TextAffinity::Upstream)
             , focusObject(nullptr)
             , focusOffset(endOffset)
+            , focusAffinity(TextAffinity::Downstream)
         { }
 
-        AXRange(AXObject* anchorObject, int anchorOffset,
-            AXObject* focusObject, int focusOffset)
+        AXRange(AXObject* anchorObject, int anchorOffset, TextAffinity anchorAffinity,
+            AXObject* focusObject, int focusOffset, TextAffinity focusAffinity)
             : anchorObject(anchorObject)
             , anchorOffset(anchorOffset)
+            , anchorAffinity(anchorAffinity)
             , focusObject(focusObject)
             , focusOffset(focusOffset)
+            , focusAffinity(focusAffinity)
         { }
 
         bool isValid() const
         {
             return ((anchorObject && focusObject)
                 || (!anchorObject && !focusObject))
                 && anchorOffset >= 0 && focusOffset >= 0;
         }
 
         // Determines if the range only refers to text offsets under the current object.
@@ skipping 463 matching lines @@
 
     static unsigned s_numberOfLiveAXObjects;
 };
 
 #define DEFINE_AX_OBJECT_TYPE_CASTS(thisType, predicate) \
     DEFINE_TYPE_CASTS(thisType, AXObject, object, object->predicate, object.predicate)
 
 } // namespace blink
 
 #endif // AXObject_h