Use text affinity to return correct accessible line boundaries.

content/renderer/accessibility/blink_ax_enum_conversion.cc

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/renderer/accessibility/blink_ax_enum_conversion.h"
 
 #include "base/logging.h"
 
 namespace content {
 
@@ skipping 533 matching lines @@
       return ui::AX_DESCRIPTION_FROM_CONTENTS;
     case blink::WebAXDescriptionFromPlaceholder:
       return ui::AX_DESCRIPTION_FROM_PLACEHOLDER;
     case blink::WebAXDescriptionFromRelatedElement:
       return ui::AX_DESCRIPTION_FROM_RELATED_ELEMENT;
   }
   NOTREACHED();
   return ui::AX_DESCRIPTION_FROM_NONE;
 }
 
+ui::AXTextAffinity AXTextAffinityFromBlink(blink::WebAXTextAffinity affinity) {
+  switch (affinity) {
+    case blink::WebAXTextAffinityUpstream:
+      return ui::AX_TEXT_AFFINITY_UPSTREAM;
+    case blink::WebAXTextAffinityDownstream:
+      return ui::AX_TEXT_AFFINITY_DOWNSTREAM;
+  }
+  NOTREACHED();
+  return ui::AX_TEXT_AFFINITY_DOWNSTREAM;
+}
+
 }  // namespace content.