Bug 1234121: Unify FocusedChild() in Accessible base class r=Jamie

Differential Revision: https://phabricator.services.mozilla.com/D154949

accessible/basetypes/Accessible.cpp

@@ -74,6 +74,16 @@ bool Accessible::IsBefore(const Accessible* aAcc) const {
   return otherPos > 0;
 }
 
+Accessible* Accessible::FocusedChild() {
+  Accessible* doc = nsAccUtils::DocumentFor(this);
+  Accessible* child = doc->FocusedChild();
+  if (child && (child == this || child->Parent() == this)) {
+    return child;
+  }
+
+  return nullptr;
+}
+
 const nsRoleMapEntry* Accessible::ARIARoleMap() const {
   return aria::GetRoleMapFromIndex(mRoleMapEntryIndex);
 }

accessible/basetypes/Accessible.h

@@ -201,6 +201,11 @@ class Accessible {
   virtual Accessible* ChildAtPoint(int32_t aX, int32_t aY,
                                    EWhichChildAtPoint aWhichChild) = 0;
 
+  /**
+   * Return the focused child if any.
+   */
+  virtual Accessible* FocusedChild();
+
   /**
    * Return ARIA role map if any.
    */

accessible/generic/ApplicationAccessible.cpp

@@ -80,7 +80,7 @@ LocalAccessible* ApplicationAccessible::LocalChildAtPoint(
   return nullptr;
 }
 
-LocalAccessible* ApplicationAccessible::FocusedChild() {
+Accessible* ApplicationAccessible::FocusedChild() {
   LocalAccessible* focus = FocusMgr()->FocusedAccessible();
   if (focus && focus->LocalParent() == this) {
     return focus;

accessible/generic/ApplicationAccessible.h

@@ -48,7 +48,7 @@ class ApplicationAccessible : public AccessibleWrap {
 
   virtual LocalAccessible* LocalChildAtPoint(
       int32_t aX, int32_t aY, EWhichChildAtPoint aWhichChild) override;
-  virtual LocalAccessible* FocusedChild() override;
+  virtual Accessible* FocusedChild() override;
 
   // ActionAccessible
   virtual KeyBinding AccessKey() const override;

accessible/generic/DocAccessible.cpp

@@ -47,8 +47,10 @@
 #include "mozilla/HTMLEditor.h"
 #include "mozilla/PresShell.h"
 #include "mozilla/StaticPrefs_accessibility.h"
+#include "mozilla/a11y/DocAccessibleParent.h"
 #include "mozilla/dom/AncestorIterator.h"
 #include "mozilla/dom/BrowserChild.h"
+#include "mozilla/dom/BrowserParent.h"
 #include "mozilla/dom/DocumentType.h"
 #include "mozilla/dom/Element.h"
 #include "mozilla/dom/HTMLSelectElement.h"
@@ -264,10 +266,34 @@ void DocAccessible::ApplyARIAState(uint64_t* aState) const {
   if (mParent) mParent->ApplyARIAState(aState);
 }
 
-LocalAccessible* DocAccessible::FocusedChild() {
+Accessible* DocAccessible::FocusedChild() {
   // Return an accessible for the current global focus, which does not have to
   // be contained within the current document.
-  return FocusMgr()->FocusedAccessible();
+  if (Accessible* focusedAcc = FocusMgr()->FocusedAccessible()) {
+    return focusedAcc;
+  }
+  nsFocusManager* focusManagerDOM = nsFocusManager::GetFocusManager();
+
+  if (!focusManagerDOM) {
+    return nullptr;
+  }
+
+  if (!XRE_IsParentProcess()) {
+    // DocAccessibleParent's don't exist in the content
+    // process, so we can't return anything useful if this
+    // is the case.
+    return nullptr;
+  }
+  // If we call GetFocusedBrowsingContext from the chrome process
+  // it returns the BrowsingContext for the focused _window_, which
+  // is not helpful here. Instead use GetFocusedBrowsingContextInChrome
+  // which returns the content BrowsingContext that has focus.
+  dom::BrowsingContext* focusedContext =
+      focusManagerDOM->GetFocusedBrowsingContextInChrome();
+
+  DocAccessibleParent* focusedDoc =
+      DocAccessibleParent::GetFrom(focusedContext);
+  return focusedDoc ? focusedDoc->GetFocusedAcc() : nullptr;
 }
 
 void DocAccessible::TakeFocus() const {

accessible/generic/DocAccessible.h

@@ -68,7 +68,7 @@ class DocAccessible : public HyperTextAccessibleWrap,
 
   virtual mozilla::a11y::ENameValueFlag Name(nsString& aName) const override;
   virtual void Description(nsString& aDescription) const override;
-  virtual LocalAccessible* FocusedChild() override;
+  virtual Accessible* FocusedChild() override;
   virtual mozilla::a11y::role NativeRole() const override;
   virtual uint64_t NativeState() const override;
   virtual uint64_t NativeInteractiveState() const override;

accessible/generic/LocalAccessible.cpp

@@ -466,15 +466,6 @@ bool LocalAccessible::NativelyUnavailable() const {
                                       nsGkAtoms::_true, eCaseMatters);
 }
 
-LocalAccessible* LocalAccessible::FocusedChild() {
-  LocalAccessible* focus = FocusMgr()->FocusedAccessible();
-  if (focus && (focus == this || focus->LocalParent() == this)) {
-    return focus;
-  }
-
-  return nullptr;
-}
-
 Accessible* LocalAccessible::ChildAtPoint(int32_t aX, int32_t aY,
                                           EWhichChildAtPoint aWhichChild) {
   Accessible* child = LocalChildAtPoint(aX, aY, aWhichChild);

accessible/generic/LocalAccessible.h

@@ -255,11 +255,6 @@ class LocalAccessible : public nsISupports, public Accessible {
   virtual Accessible* ChildAtPoint(int32_t aX, int32_t aY,
                                    EWhichChildAtPoint aWhichChild) override;
 
-  /**
-   * Return the focused child if any.
-   */
-  virtual LocalAccessible* FocusedChild();
-
   virtual Relation RelationByType(RelationType aType) const override;
 
   //////////////////////////////////////////////////////////////////////////////

accessible/ipc/DocAccessibleParent.cpp

@@ -15,6 +15,7 @@
 #include "xpcAccEvents.h"
 #include "nsAccUtils.h"
 #include "TextRange.h"
+#include "RootAccessible.h"
 
 #if defined(XP_WIN)
 #  include "AccessibleWrap.h"
@@ -22,7 +23,6 @@
 #  include "mozilla/mscom/PassthruProxy.h"
 #  include "mozilla/mscom/Ptr.h"
 #  include "nsWinUtils.h"
-#  include "RootAccessible.h"
 #else
 #  include "mozilla/a11y/DocAccessiblePlatformExtParent.h"
 #endif
@@ -1275,6 +1275,16 @@ void DocAccessibleParent::SelectionRanges(nsTArray<TextRange>* aRanges) const {
   }
 }
 
+Accessible* DocAccessibleParent::FocusedChild() {
+  LocalAccessible* outerDoc = OuterDocOfRemoteBrowser();
+  if (!outerDoc) {
+    return nullptr;
+  }
+
+  RootAccessible* rootDocument = outerDoc->RootAccessible();
+  return rootDocument->FocusedChild();
+}
+
 void DocAccessibleParent::URL(nsAString& aURL) const {
   if (!mBrowsingContext) {
     return;

accessible/ipc/DocAccessibleParent.h

@@ -317,6 +317,8 @@ class DocAccessibleParent : public RemoteAccessible,
 
   virtual void SelectionRanges(nsTArray<TextRange>* aRanges) const override;
 
+  virtual Accessible* FocusedChild() override;
+
   void URL(nsAString& aURL) const;
 
   // Tracks cached reverse relations (ie. those not set explicitly by an

accessible/ipc/RemoteAccessibleShared.h

@@ -187,7 +187,6 @@ double MaxValue() const override;
 double Step() const override;
 bool SetCurValue(double aValue);
 
-RemoteAccessible* FocusedChild();
 Accessible* ChildAtPoint(
     int32_t aX, int32_t aY,
     LocalAccessible::EWhichChildAtPoint aWhichChild) override;

accessible/ipc/other/DocAccessibleChild.cpp

@@ -1416,50 +1416,6 @@ mozilla::ipc::IPCResult DocAccessibleChild::RecvStep(const uint64_t& aID,
   return IPC_OK();
 }
 
-mozilla::ipc::IPCResult DocAccessibleChild::RecvFocusedChild(
-    const uint64_t& aID, PDocAccessibleChild** aResultDoc,
-    uint64_t* aResultID) {
-  *aResultDoc = nullptr;
-  *aResultID = 0;
-  LocalAccessible* acc = IdToAccessible(aID);
-  if (!acc) {
-    return IPC_OK();
-  }
-
-  LocalAccessible* result = acc->FocusedChild();
-  if (result) {
-    // LocalAccessible::FocusedChild can return a LocalAccessible from any
-    // document, not just a descendant of the caller's document. Check that it
-    // is really a descendant.
-    DocAccessible* doc = result->Document();
-    if (!doc) {
-      MOZ_ASSERT_UNREACHABLE("Focused child is unbound from doc.");
-      return IPC_OK();
-    }
-
-    while (doc != mDoc) {
-      doc = doc->ParentDocument();
-      if (!doc) {
-        // result's document is not a descendant.
-        return IPC_OK();
-      }
-    }
-    DocAccessibleChild* resultDoc = result->Document()->IPCDoc();
-    // We've sent the constructor for this document to the parent process.
-    // However, because the constructor is async, the parent process might
-    // get the result of this (sync) method before it runs the constructor.
-    // If we send this document in this case, the parent process will crash.
-    // Therefore, we only do this if the parent process has explicitly told
-    // us that the document has been constructed there.
-    if (resultDoc && resultDoc->IsConstructedInParentProcess()) {
-      *aResultDoc = resultDoc;
-      *aResultID =
-          result->IsDoc() ? 0 : reinterpret_cast<uint64_t>(result->UniqueID());
-    }
-  }
-  return IPC_OK();
-}
-
 mozilla::ipc::IPCResult DocAccessibleChild::RecvLanguage(const uint64_t& aID,
                                                          nsString* aLocale) {
   LocalAccessible* acc = IdToAccessible(aID);

accessible/ipc/other/DocAccessibleChild.h

@@ -417,10 +417,6 @@ class DocAccessibleChild : public DocAccessibleChildBase {
   virtual mozilla::ipc::IPCResult RecvStep(const uint64_t& aID,
                                            double* aStep) override;
 
-  virtual mozilla::ipc::IPCResult RecvFocusedChild(
-      const uint64_t& aID, PDocAccessibleChild** aResultDoc,
-      uint64_t* aResultID) override;
-
   virtual mozilla::ipc::IPCResult RecvLanguage(const uint64_t& aID,
                                                nsString* aLocale) override;
   virtual mozilla::ipc::IPCResult RecvDocType(const uint64_t& aID,

accessible/ipc/other/PDocAccessible.ipdl

@@ -330,8 +330,6 @@ child:
   [Nested=inside_sync] sync Step(uint64_t aID) returns(double aStep);
 
   async TakeFocus(uint64_t aID);
-  [Nested=inside_sync] sync FocusedChild(uint64_t aID)
-    returns(nullable PDocAccessible aResultDoc, uint64_t aResultID);
 
   [Nested=inside_sync] sync Language(uint64_t aID) returns(nsString aLocale);
   [Nested=inside_sync] sync DocType(uint64_t aID) returns(nsString aType);

accessible/ipc/other/RemoteAccessible.cpp

@@ -888,45 +888,6 @@ double RemoteAccessible::Step() const {
   return step;
 }
 
-RemoteAccessible* RemoteAccessible::FocusedChild() {
-  if (IsOuterDoc()) {
-    // If FocusedChild was called on an outer doc, it should behave
-    // like a non-doc accessible and return its focused child, or null.
-    // If the inner doc is OOP (fission), calling FocusedChild on the outer
-    // doc would return null.
-    RemoteAccessible* child = RemoteFirstChild();
-    if (!child) {
-      return (State() & states::FOCUSED) ? this : nullptr;
-    }
-    MOZ_ASSERT(child->IsDoc());
-    return (child->State() & states::FOCUSED) ? child : nullptr;
-  }
-
-  auto* doc = mDoc;
-  uint64_t id = mID;
-  if (IsDoc()) {
-    // If this is a doc we should return the focused descendant, not just the
-    // direct child. In order to do that, we need to get a doc that is in
-    // the same process as the focused accessible. So we need the focused doc.
-    if (dom::BrowserParent* browser = dom::BrowserParent::GetFocused()) {
-      if (auto* focusedDoc = browser->GetTopLevelDocAccessible()) {
-        if (!focusedDoc->IsTopLevel()) {
-          // Redirect SendFocusedChild to OOP iframe doc.
-          doc = focusedDoc;
-        }
-      }
-    }
-  }
-
-  PDocAccessibleParent* resultDoc = nullptr;
-  uint64_t resultID = 0;
-  Unused << doc->SendFocusedChild(id, &resultDoc, &resultID);
-
-  auto* useDoc = static_cast<DocAccessibleParent*>(resultDoc);
-  // If useDoc is null, this means there is no focused child.
-  return useDoc ? useDoc->GetAccessible(resultID) : nullptr;
-}
-
 Accessible* RemoteAccessible::ChildAtPoint(
     int32_t aX, int32_t aY, LocalAccessible::EWhichChildAtPoint aWhichChild) {
   if (StaticPrefs::accessibility_cache_enabled_AtStartup()) {

accessible/mac/mozAccessible.mm

@@ -227,33 +227,12 @@ static const uint64_t kCacheInitialized = ((uint64_t)0x1) << 63;
 
 - (id)moxFocusedUIElement {
   MOZ_ASSERT(mGeckoAccessible);
-
-  LocalAccessible* acc = mGeckoAccessible->AsLocal();
-  RemoteAccessible* proxy = mGeckoAccessible->AsRemote();
-
-  mozAccessible* focusedChild = nil;
-  if (acc) {
-    LocalAccessible* focusedGeckoChild = acc->FocusedChild();
-    if (focusedGeckoChild) {
-      focusedChild = GetNativeFromGeckoAccessible(focusedGeckoChild);
-    } else {
-      dom::BrowserParent* browser = dom::BrowserParent::GetFocused();
-      if (browser) {
-        a11y::DocAccessibleParent* proxyDoc =
-            browser->GetTopLevelDocAccessible();
-        if (proxyDoc) {
-          mozAccessible* nativeRemoteChild =
-              GetNativeFromGeckoAccessible(proxyDoc);
-          return [nativeRemoteChild accessibilityFocusedUIElement];
-        }
-      }
-    }
-  } else if (proxy) {
-    RemoteAccessible* focusedGeckoChild = proxy->FocusedChild();
-    if (focusedGeckoChild) {
-      focusedChild = GetNativeFromGeckoAccessible(focusedGeckoChild);
-    }
-  }
+  // This only gets queried on the web area or the root group
+  // so just use the doc's focused child instead of trying to get
+  // the focused child of mGeckoAccessible.
+  Accessible* doc = nsAccUtils::DocumentFor(mGeckoAccessible);
+  mozAccessible* focusedChild =
+      GetNativeFromGeckoAccessible(doc->FocusedChild());
 
   if ([focusedChild isAccessibilityElement]) {
     return focusedChild;

accessible/tests/browser/fission/browser_take_focus.js

@@ -19,6 +19,7 @@ addAccessibleTask(
       contentDocAcc,
       "default-iframe-body-id"
     );
+    const root = getRootAccessible(document);
 
     testStates(textbox, STATE_FOCUSABLE, 0, STATE_FOCUSED);
 
@@ -28,11 +29,6 @@ addAccessibleTask(
 
     testStates(textbox, STATE_FOCUSABLE | STATE_FOCUSED, 0);
 
-    if (Services.appinfo.OS == "WINNT") {
-      // focusedChild XPCOM method not implemented in windows.
-      return;
-    }
-
     is(
       getAccessibleDOMNodeID(contentDocAcc.focusedChild),
       "textbox",
@@ -42,7 +38,13 @@ addAccessibleTask(
     is(
       getAccessibleDOMNodeID(iframeDocAcc.focusedChild),
       "textbox",
-      "correct focusedChild from child doc"
+      "correct focusedChild from iframe"
+    );
+
+    is(
+      getAccessibleDOMNodeID(root.focusedChild),
+      "textbox",
+      "correct focusedChild from root"
     );
 
     ok(!iframe.focusedChild, "correct focusedChild from iframe (null)");
@@ -61,6 +63,11 @@ addAccessibleTask(
       "default-iframe-body-id",
       "correct focusedChild of child doc from iframe"
     );
+    is(
+      getAccessibleDOMNodeID(root.focusedChild),
+      "default-iframe-body-id",
+      "correct focusedChild of child doc from root"
+    );
   },
   { topLevel: false, iframe: true, remoteIframe: true }
 );

accessible/windows/msaa/MsaaAccessible.cpp

@@ -1267,15 +1267,9 @@ MsaaAccessible::get_accFocus(
   if (!mAcc) {
     return CO_E_OBJNOTCONNECTED;
   }
-  LocalAccessible* localAcc = LocalAcc();
-  if (!localAcc) {
-    return E_NOTIMPL;  // XXX Not supported for RemoteAccessible yet.
-  }
-
   // Return the current IAccessible child that has focus
-  LocalAccessible* focusedAccessible = localAcc->FocusedChild();
-
-  if (focusedAccessible == localAcc) {
+  Accessible* focusedAccessible = mAcc->FocusedChild();
+  if (focusedAccessible == mAcc) {
     pvarChild->vt = VT_I4;
     pvarChild->lVal = CHILDID_SELF;
   } else if (focusedAccessible) {

accessible/windows/msaa/MsaaRootAccessible.cpp

@@ -66,54 +66,48 @@ already_AddRefed<IUnknown> MsaaRootAccessible::GetInternalUnknown() {
 ////////////////////////////////////////////////////////////////////////////////
 // MsaaRootAccessible
 STDMETHODIMP
-MsaaRootAccessible::get_accFocus(
-    /* [retval][out] */ VARIANT __RPC_FAR* pvarChild) {
-  HRESULT hr = MsaaDocAccessible::get_accFocus(pvarChild);
-  if (FAILED(hr) || pvarChild->vt != VT_EMPTY || !IsWin8OrLater()) {
-    // 1. We got a definite result (either failure or an accessible); or
-    // 2. This is Windows 7, where we don't want to retrieve the focus from a
-    // remote document because this causes mysterious intermittent crashes
-    // when we're called by UIA clients; see bug 1424505.
-    return hr;
+MsaaRootAccessible::accNavigate(
+    /* [in] */ long navDir,
+    /* [optional][in] */ VARIANT varStart,
+    /* [retval][out] */ VARIANT __RPC_FAR* pvarEndUpAt) {
+  // Special handling for NAVRELATION_EMBEDS.
+  // When we only have a single process, this can be handled the same way as
+  // any other relation.
+  // However, for multi process, the normal relation mechanism doesn't work
+  // because it can't handle remote objects.
+  if (navDir != NAVRELATION_EMBEDS || varStart.vt != VT_I4 ||
+      varStart.lVal != CHILDID_SELF) {
+    // We only handle EMBEDS on the root here.
+    // Forward to the base implementation.
+    return MsaaDocAccessible::accNavigate(navDir, varStart, pvarEndUpAt);
   }
 
-  // The base implementation reported no focus.
-  // Focus might be in a remote document.
-  // (The base implementation can't handle this.)
-  if (StaticPrefs::accessibility_cache_enabled_AtStartup()) {
-    return S_FALSE;
+  if (!pvarEndUpAt) {
+    return E_INVALIDARG;
   }
-  dom::BrowserParent* browser = dom::BrowserParent::GetFocused();
-  if (!browser) {
-    return hr;
+  RootAccessible* rootAcc = RootAcc();
+  if (!rootAcc) {
+    return CO_E_OBJNOTCONNECTED;
   }
-  DocAccessibleParent* docProxy = browser->GetTopLevelDocAccessible();
-  if (!docProxy) {
-    return hr;
+
+  Accessible* target = nullptr;
+  // Get the document in the active tab.
+  RemoteAccessible* docProxy = rootAcc->GetPrimaryRemoteTopLevelContentDoc();
+  if (docProxy) {
+    target = docProxy;
+  } else {
+    // The base implementation could handle this, but we may as well
+    // just handle it here.
+    Relation rel = rootAcc->RelationByType(RelationType::EMBEDS);
+    target = rel.Next();
   }
-  RefPtr<IDispatch> docDisp = already_AddRefed(NativeAccessible(docProxy));
-  if (!docDisp) {
+
+  if (!target) {
     return E_FAIL;
   }
-  RefPtr<IAccessible> docIa;
-  hr = docDisp->QueryInterface(IID_IAccessible, (void**)getter_AddRefs(docIa));
-  MOZ_ASSERT(SUCCEEDED(hr));
-  MOZ_ASSERT(docIa);
-
-  // Ask this document for its focused descendant.
-  // We return this as is to the client except for CHILDID_SELF (see below).
-  hr = docIa->get_accFocus(pvarChild);
-  if (FAILED(hr)) {
-    return hr;
-  }
-
-  if (pvarChild->vt == VT_I4 && pvarChild->lVal == CHILDID_SELF) {
-    // The document itself has focus.
-    // We're handling a call to accFocus on the root accessible,
-    // so replace CHILDID_SELF with the document accessible.
-    pvarChild->vt = VT_DISPATCH;
-    docDisp.forget(&pvarChild->pdispVal);
-  }
 
+  VariantInit(pvarEndUpAt);
+  pvarEndUpAt->pdispVal = NativeAccessible(target);
+  pvarEndUpAt->vt = VT_DISPATCH;
   return S_OK;
 }

accessible/windows/msaa/MsaaRootAccessible.h

@@ -35,8 +35,10 @@ class MsaaRootAccessible : public MsaaDocAccessible {
    */
   already_AddRefed<IUnknown> GetInternalUnknown();
 
-  virtual /* [id][propget] */ HRESULT STDMETHODCALLTYPE get_accFocus(
-      /* [retval][out] */ VARIANT __RPC_FAR* pvarChild) override;
+  virtual /* [id] */ HRESULT STDMETHODCALLTYPE accNavigate(
+      /* [in] */ long navDir,
+      /* [optional][in] */ VARIANT varStart,
+      /* [retval][out] */ VARIANT __RPC_FAR* pvarEndUpAt) override;
 
  private:
   // DECLARE_AGGREGATABLE declares the internal IUnknown methods as well as

accessible/xpcom/xpcAccessible.cpp

@@ -552,15 +552,7 @@ xpcAccessible::GetFocusedChild(nsIAccessible** aChild) {
 
   if (!IntlGeneric()) return NS_ERROR_FAILURE;
 
-  if (RemoteAccessible* proxy = IntlGeneric()->AsRemote()) {
-#if defined(XP_WIN)
-    return NS_ERROR_NOT_IMPLEMENTED;
-#else
-    NS_IF_ADDREF(*aChild = ToXPC(proxy->FocusedChild()));
-#endif
-  } else {
-    NS_IF_ADDREF(*aChild = ToXPC(Intl()->FocusedChild()));
-  }
+  NS_IF_ADDREF(*aChild = ToXPC(IntlGeneric()->FocusedChild()));
 
   return NS_OK;
 }

accessible/xul/XULTreeAccessible.cpp

@@ -612,7 +612,7 @@ NS_IMPL_ISUPPORTS_CYCLE_COLLECTION_INHERITED(XULTreeItemAccessibleBase,
 ////////////////////////////////////////////////////////////////////////////////
 // XULTreeItemAccessibleBase: LocalAccessible
 
-LocalAccessible* XULTreeItemAccessibleBase::FocusedChild() {
+Accessible* XULTreeItemAccessibleBase::FocusedChild() {
   return FocusMgr()->FocusedAccessible() == this ? this : nullptr;
 }
 

accessible/xul/XULTreeAccessible.h

@@ -152,7 +152,7 @@ class XULTreeItemAccessibleBase : public AccessibleWrap {
   virtual uint64_t NativeInteractiveState() const override;
   virtual int32_t IndexInParent() const override;
   virtual Relation RelationByType(RelationType aType) const override;
-  virtual LocalAccessible* FocusedChild() override;
+  virtual Accessible* FocusedChild() override;
   virtual void SetSelected(bool aSelect) override;
   virtual void TakeFocus() const override;
 

accessible/xul/XULTreeGridAccessible.cpp

@@ -386,7 +386,7 @@ void XULTreeGridCellAccessible::Shutdown() {
   LeafAccessible::Shutdown();
 }
 
-LocalAccessible* XULTreeGridCellAccessible::FocusedChild() { return nullptr; }
+Accessible* XULTreeGridCellAccessible::FocusedChild() { return nullptr; }
 
 ENameValueFlag XULTreeGridCellAccessible::Name(nsString& aName) const {
   aName.Truncate();

accessible/xul/XULTreeGridAccessible.h

@@ -125,7 +125,7 @@ class XULTreeGridCellAccessible : public LeafAccessible,
   virtual nsRect BoundsInAppUnits() const override;
   virtual nsIntRect BoundsInCSSPixels() const override;
   virtual ENameValueFlag Name(nsString& aName) const override;
-  virtual LocalAccessible* FocusedChild() override;
+  virtual Accessible* FocusedChild() override;
   virtual already_AddRefed<AccAttributes> NativeAttributes() override;
   virtual int32_t IndexInParent() const override;
   virtual Relation RelationByType(RelationType aType) const override;