Move handling of DraggableRegionsChanged notification from "view" to "frame".

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

 /*
  * Copyright (C) 1998, 1999 Torben Weis <weis@kde.org>
  *                     1999 Lars Knoll <knoll@kde.org>
  *                     1999 Antti Koivisto <koivisto@kde.org>
  *                     2000 Dirk Mueller <mueller@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
  *           (C) 2006 Graham Dennis (graham.dennis@gmail.com)
  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
@@ skipping 2804 matching lines @@
 
 void LocalFrameView::UpdateDocumentAnnotatedRegions() const {
   Document* document = frame_->GetDocument();
   if (!document->HasAnnotatedRegions())
     return;
   Vector<AnnotatedRegionValue> new_regions;
   CollectAnnotatedRegions(*(document->GetLayoutBox()), new_regions);
   if (new_regions == document->AnnotatedRegions())
     return;
   document->SetAnnotatedRegions(new_regions);
-  if (Page* page = frame_->GetPage())
-    page->GetChromeClient().AnnotatedRegionsChanged();
+
+  // Client should always be present, because this method cannot be called
+  // during detach (LocalFrame::Detach calls SetView(nullptr)).

[dcheng, 2017/06/08 20:02:56]

I would omit this comment: the precise details of this are likely to change over
time. I plan on documenting lifecycle things more thoroughly in a separate
README.md file.

[Łukasz Anforowicz, 2017/06/08 20:51:37]

Done.

+  DCHECK(frame_->Client());
+  frame_->Client()->AnnotatedRegionsChanged();
 }
 
 void LocalFrameView::DidAttachDocument() {
   Page* page = frame_->GetPage();
   DCHECK(page);
 
   DCHECK(frame_->GetDocument());
 
   if (frame_->IsMainFrame()) {
     ScrollableArea& visual_viewport = frame_->GetPage()->GetVisualViewport();
@@ skipping 2561 matching lines @@
 void LocalFrameView::SetAnimationHost(
     std::unique_ptr<CompositorAnimationHost> host) {
   animation_host_ = std::move(host);
 }
 
 LayoutUnit LocalFrameView::CaretWidth() const {
   return LayoutUnit(GetChromeClient()->WindowToViewportScalar(1));
 }
 
 }  // namespace blink