Send AXLayoutComplete even when document hasn't finished loading yet (reland)

Source/core/frame/FrameView.cpp

Index: Source/core/frame/FrameView.cpp
diff --git a/Source/core/frame/FrameView.cpp b/Source/core/frame/FrameView.cpp
index 0565e76ae0136c47e47b11680c4ecfaf928c1f7f..9190c8e7529995e6ddc55ccc845214cfb476146c 100644
--- a/Source/core/frame/FrameView.cpp
+++ b/Source/core/frame/FrameView.cpp
@@ -983,8 +983,8 @@ void FrameView::layout(bool allowSubtree)
 
     m_layoutCount++;
 
-    if (AXObjectCache* cache = rootForThisLayout->document().existingAXObjectCache())
-        cache->postNotification(rootForThisLayout, AXObjectCache::AXLayoutComplete, true);
+    if (AXObjectCache* cache = rootForThisLayout->document().axObjectCache())
+        cache->handleLayoutComplete(rootForThisLayout);
     updateAnnotatedRegions();
 
     ASSERT(!rootForThisLayout->needsLayout());