One accessibility tree per frame.

third_party/WebKit/Source/core/dom/Document.cpp

Index: third_party/WebKit/Source/core/dom/Document.cpp
diff --git a/third_party/WebKit/Source/core/dom/Document.cpp b/third_party/WebKit/Source/core/dom/Document.cpp
index 64f72e837e40d3a5cb3d7d72c4b4a0cc95adb60d..1f2a3fc70b1c1b42fac64c7840c09e0f01512a94 100644
--- a/third_party/WebKit/Source/core/dom/Document.cpp
+++ b/third_party/WebKit/Source/core/dom/Document.cpp
@@ -2322,30 +2322,11 @@ void Document::removeAllEventListeners()
 
 Document& Document::axObjectCacheOwner() const
 {
-    // FIXME(dmazzoni): Currently there's one AXObjectCache per page, owned
-    // by the top document, but with --site-isolation the top document may
-    // be a remote frame. As a quick fix we're making the local root the owner
-    // of the AXObjectCache (http://crbug.com/510410), but the proper fix
-    // will be for each Document to  have its own AXObjectCache
-    // (http://crbug.com/532249).
     Document* top = const_cast<Document*>(this);
-    LocalFrame* frame = this->frame();
-    if (!frame)
-        return *top;
-
-    // This loop is more efficient than calling localFrameRoot.
-    while (frame && frame->owner() && frame->owner()->isLocal()) {
-        HTMLFrameOwnerElement* owner = toHTMLFrameOwnerElement(frame->owner());
-        top = &owner->document();
-        frame = top->frame();
-    }
-
     if (top->frame() && top->frame()->pagePopupOwner()) {
         ASSERT(!top->m_axObjectCache);
         return top->frame()->pagePopupOwner()->document().axObjectCacheOwner();
     }
-
-    ASSERT(top);
     return *top;
 }