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 93a13ab219b2a1740691546634dd51c213453042..451bbabdae956c35fed3adb75d42d315bd89a641 100644
--- a/third_party/WebKit/Source/core/dom/Document.cpp
+++ b/third_party/WebKit/Source/core/dom/Document.cpp
@@ -2320,30 +2320,11 @@ 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);

[dcheng, 2016/03/08 01:14:27]

Document* doc?

[dmazzoni, 2016/03/08 18:51:03]

Done.

-    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()) {

[dcheng, 2016/03/08 01:14:27]

Part of me wonders if this warrants a comment of some sort. Page popups are kind
of weird and poorly documented.

[dmazzoni, 2016/03/08 18:51:03]

Done.

         ASSERT(!top->m_axObjectCache);
         return top->frame()->pagePopupOwner()->document().axObjectCacheOwner();
     }
-
-    ASSERT(top);
     return *top;
 }