Initial containing block for print not affected by page zoom.

third_party/WebKit/Source/core/frame/FrameView.h

 /*
    Copyright (C) 1997 Martin Jones (mjones@kde.org)
              (C) 1998 Waldo Bastian (bastian@kde.org)
              (C) 1998, 1999 Torben Weis (weis@kde.org)
              (C) 1999 Lars Knoll (knoll@kde.org)
              (C) 1999 Antti Koivisto (koivisto@kde.org)
    Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights
    reserved.
 
    This library is free software; you can redistribute it and/or
@@ skipping 742 matching lines @@
   bool needsPaintPropertyUpdate() const { return m_needsPaintPropertyUpdate; }
 
   // Set when the whole frame subtree needs full paint property update,
   // e.g. when beginning or finishing printing.
   void setSubtreeNeedsPaintPropertyUpdate();
 
   // TODO(ojan): Merge this with IntersectionObserver once it lands.
   IntRect computeVisibleArea();
 
   // Viewport size that should be used for viewport units (i.e. 'vh'/'vw').
+  // May include the size of browser controls. See implementation for further
+  // documentation.
   FloatSize viewportSizeForViewportUnits() const;
 
+  // Initial containing block size for evaluating viewport-dependent media
+  // queries.
+  FloatSize viewportSizeForMediaQueries() const;
+
   ScrollAnchor* scrollAnchor() override { return &m_scrollAnchor; }
   void clearScrollAnchor();
   bool shouldPerformScrollAnchoring() const override;
   void enqueueScrollAnchoringAdjustment(ScrollableArea*);
   void performScrollAnchoringAdjustments();
 
   // For PaintInvalidator temporarily. TODO(wangxianzhu): Move into
   // PaintInvalidator.
   void invalidatePaintIfNeeded(const PaintInvalidationState&);
 
@@ skipping 485 matching lines @@
                   frameViewBase.isFrameView());
 DEFINE_TYPE_CASTS(FrameView,
                   ScrollableArea,
                   scrollableArea,
                   scrollableArea->isFrameView(),
                   scrollableArea.isFrameView());
 
 }  // namespace blink
 
 #endif  // FrameView_h