One accessibility tree per frame.

third_party/WebKit/Source/core/frame/FrameView.cpp

Index: third_party/WebKit/Source/core/frame/FrameView.cpp
diff --git a/third_party/WebKit/Source/core/frame/FrameView.cpp b/third_party/WebKit/Source/core/frame/FrameView.cpp
index 5973ff23a0c8405835530846834810eee2cf0d52..7725566cd96de2cc4b460e883e9c67996694fa85 100644
--- a/third_party/WebKit/Source/core/frame/FrameView.cpp
+++ b/third_party/WebKit/Source/core/frame/FrameView.cpp
@@ -250,12 +250,6 @@ void FrameView::forAllNonThrottledFrameViews(Function function)
     }
 }
 
-void FrameView::removeFromAXObjectCache()
-{
-    if (AXObjectCache* cache = axObjectCache())
-        cache->childrenChanged(m_frame->pagePopupOwner());
-}
-
 void FrameView::init()
 {
     reset();
@@ -277,10 +271,6 @@ void FrameView::dispose()
 
     detachScrollbars();
 
-    // When the view is no longer associated with a frame, it needs to be removed from the ax object cache
-    // right now, otherwise it won't be able to reach the topDocument()'s axObject cache later.
-    removeFromAXObjectCache();
-
     if (ScrollingCoordinator* scrollingCoordinator = this->scrollingCoordinator())
         scrollingCoordinator->willDestroyScrollableArea(this);