Use const ref for LocalFrame::LocalFrameRoot and FrameTree::Top

third_party/WebKit/Source/core/page/FocusController.cpp

 /*
  * Copyright (C) 2006, 2007 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Nuanti Ltd.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 804 matching lines @@
   return ToLocalFrame(focused_frame_.Get());
 }
 
 Frame* FocusController::FocusedOrMainFrame() const {
   if (LocalFrame* frame = FocusedFrame())
     return frame;
 
   // FIXME: This is a temporary hack to ensure that we return a LocalFrame, even
   // when the mainFrame is remote.  FocusController needs to be refactored to
   // deal with RemoteFrames cross-process focus transfers.
-  for (Frame* frame = page_->MainFrame()->Tree().Top(); frame;
+  for (Frame* frame = &page_->MainFrame()->Tree().Top(); frame;
        frame = frame->Tree().TraverseNext()) {
     if (frame->IsLocalRoot())
       return frame;
   }
 
   return page_->MainFrame();
 }
 
 HTMLFrameOwnerElement* FocusController::FocusedFrameOwnerElement(
     LocalFrame& current_frame) const {
@@ skipping 135 matching lines @@
       current ? ScopedFocusNavigation::CreateFor(*current)
               : ScopedFocusNavigation::CreateForDocument(*document);
   Element* element = FindFocusableElementAcrossFocusScopes(type, scope);
   if (!element) {
     // If there's a RemoteFrame on the ancestor chain, we need to continue
     // searching for focusable elements there.
     if (frame->LocalFrameRoot() != frame->Tree().Top()) {
       document->ClearFocusedElement();
       document->SetSequentialFocusNavigationStartingPoint(nullptr);
       SetFocusedFrame(nullptr);
-      ToRemoteFrame(frame->LocalFrameRoot()->Tree().Parent())
-          ->AdvanceFocus(type, frame->LocalFrameRoot());
+      ToRemoteFrame(frame->LocalFrameRoot().Tree().Parent())
+          ->AdvanceFocus(type, &frame->LocalFrameRoot());
       return true;
     }
 
     // We didn't find an element to focus, so we should try to pass focus to
     // Chrome.
     if (!initial_focus && page_->GetChromeClient().CanTakeFocus(type)) {
       document->ClearFocusedElement();
       document->SetSequentialFocusNavigationStartingPoint(nullptr);
       SetFocusedFrame(nullptr);
       page_->GetChromeClient().TakeFocus(type);
@@ skipping 144 matching lines @@
 
 void FocusController::SetActive(bool active) {
   if (is_active_ == active)
     return;
 
   is_active_ = active;
 
   Frame* frame = FocusedOrMainFrame();
   if (frame->IsLocalFrame()) {
     Document* const document =
-        ToLocalFrame(frame)->LocalFrameRoot()->GetDocument();
+        ToLocalFrame(frame)->LocalFrameRoot().GetDocument();
     DCHECK(document);
     if (!document->IsActive())
       return;
     // Invalidate all custom scrollbars because they support the CSS
     // window-active attribute. This should be applied to the entire page so
     // we invalidate from the root FrameView instead of just the focused.
     if (FrameView* view = document->View())
       view->InvalidateAllCustomScrollbarsOnActiveChanged();
     ToLocalFrame(frame)->Selection().PageActivationChanged();
   }
@@ skipping 252 matching lines @@
     it->FocusedFrameChanged();
 }
 
 DEFINE_TRACE(FocusController) {
   visitor->Trace(page_);
   visitor->Trace(focused_frame_);
   visitor->Trace(focus_changed_observers_);
 }
 
 }  // namespace blink