Fix live regions on Mac OS X.

content/renderer/accessibility/blink_ax_tree_source.cc

 // Copyright 2014 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_tree_source.h"
 
 #include <set>
 
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_util.h"
@@ skipping 367 matching lines @@
         dst->AddBoolAttribute(ui::AX_ATTR_IS_AX_TREE_HOST, true);
       }
     }
   }
 
   if (src.isInLiveRegion()) {
     dst->AddBoolAttribute(ui::AX_ATTR_LIVE_ATOMIC, src.liveRegionAtomic());
     dst->AddBoolAttribute(ui::AX_ATTR_LIVE_BUSY, src.liveRegionBusy());
     if (src.liveRegionBusy())
       dst->state |= (1 << ui::AX_STATE_BUSY);
-    dst->AddStringAttribute(ui::AX_ATTR_LIVE_STATUS,
-                            UTF16ToUTF8(src.liveRegionStatus()));
+    if (!src.liveRegionStatus().isEmpty()) {
+      dst->AddStringAttribute(ui::AX_ATTR_LIVE_STATUS,
+                              UTF16ToUTF8(src.liveRegionStatus()));
+    }
     dst->AddStringAttribute(ui::AX_ATTR_LIVE_RELEVANT,
                             UTF16ToUTF8(src.liveRegionRelevant()));
     dst->AddBoolAttribute(ui::AX_ATTR_CONTAINER_LIVE_ATOMIC,
                           src.containerLiveRegionAtomic());
     dst->AddBoolAttribute(ui::AX_ATTR_CONTAINER_LIVE_BUSY,
                           src.containerLiveRegionBusy());
     dst->AddStringAttribute(ui::AX_ATTR_CONTAINER_LIVE_STATUS,
                             UTF16ToUTF8(src.containerLiveRegionStatus()));
     dst->AddStringAttribute(ui::AX_ATTR_CONTAINER_LIVE_RELEVANT,
                             UTF16ToUTF8(src.containerLiveRegionRelevant()));
@@ skipping 162 matching lines @@
     AddIntListAttributeFromWebObjects(ui::AX_ATTR_OWNS_IDS, owns, dst);
 }
 
 blink::WebDocument BlinkAXTreeSource::GetMainDocument() const {
   if (render_frame_ && render_frame_->GetWebFrame())
     return render_frame_->GetWebFrame()->document();
   return WebDocument();
 }
 
 }  // namespace content