Clean compositing inputs for location APIs for sticky-affected elements.

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

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012 Apple Inc. All
  * rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved.
  * (http://www.torchmobile.com/)
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
@@ skipping 496 matching lines @@
   enum RunPostLayoutTasks {
     kRunPostLayoutTasksAsyhnchronously,
     kRunPostLayoutTasksSynchronously,
   };
   void UpdateStyleAndLayoutIgnorePendingStylesheets(
       RunPostLayoutTasks = kRunPostLayoutTasksAsyhnchronously);
   void UpdateStyleAndLayoutIgnorePendingStylesheetsForNode(Node*);
   PassRefPtr<ComputedStyle> StyleForElementIgnoringPendingStylesheets(Element*);
   PassRefPtr<ComputedStyle> StyleForPage(int page_index);
 
+  // Ensures that location-based data will be valid for a given node.
+  //
+  // This will involve running style and layout if they are currently dirty, and
+  // it may also run compositing inputs as well if the node is in a sticky
+  // subtree (as the sticky offset may change the node's position).
+  //
+  // Due to this you should only call this if you definitely need valid location
+  // data, otherwise use one of the |UpdateStyleAndLayout...| methods above.
+  void EnsureAuxiliaryLocationDataValidForNode(const Node*);

[flackr, 2017/05/04 19:00:51]

Maybe we should call this EnsurePaintLocationDataValidForNode? Since sticky is a
paint effect, and the only one which affects location it is the only affect
requiring cleaning of paint related inputs.

I also have a preference for keeping the naming consistent. I.e.
EnsurePaintLocationDataValidForNode and calling the bit
location_requires_paint_clean (or something to that effect) or
EnsureStickyLocationDataValidForNode and location_requires_sticky_data.

[smcgruer, 2017/05/08 14:32:06]

Done.

+
   // Returns true if page box (margin boxes and page borders) is visible.
   bool IsPageBoxVisible(int page_index);
 
   // Returns the preferred page size and margins in pixels, assuming 96
   // pixels per inch. pageSize, marginTop, marginRight, marginBottom,
   // marginLeft must be initialized to the default values that are used if
   // auto is specified.
   void PageSizeAndMarginsInPixels(int page_index,
                                   DoubleSize& page_size,
                                   int& margin_top,
@@ skipping 1207 matching lines @@
 DEFINE_TYPE_CASTS(TreeScope, Document, document, true, true);
 
 }  // namespace blink
 
 #ifndef NDEBUG
 // Outside the WebCore namespace for ease of invocation from gdb.
 CORE_EXPORT void showLiveDocumentInstances();
 #endif
 
 #endif  // Document_h