Initial containing block for print not affected by page zoom.

third_party/WebKit/Source/core/frame/FrameView.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 1387 matching lines @@
     if (parentRect.isEmpty())
       return IntRect();
 
     us.intersect(parentRect);
   }
 
   return us;
 }
 
 FloatSize FrameView::viewportSizeForViewportUnits() const {
-  float zoom = frame().pageZoomFactor();
+  float zoom = 1;
+  if (!m_frame->document() || !m_frame->document()->printing())
+    zoom = frame().pageZoomFactor();
 
   LayoutViewItem layoutViewItem = this->layoutViewItem();
   if (layoutViewItem.isNull())
     return FloatSize();
 
   FloatSize layoutSize;
   layoutSize.setWidth(layoutViewItem.viewWidth(IncludeScrollbars) / zoom);
   layoutSize.setHeight(layoutViewItem.viewHeight(IncludeScrollbars) / zoom);
 
   BrowserControls& browserControls = m_frame->page()->browserControls();
@@ skipping 3834 matching lines @@
 void FrameView::setAnimationHost(
     std::unique_ptr<CompositorAnimationHost> host) {
   m_animationHost = std::move(host);
 }
 
 LayoutUnit FrameView::caretWidth() const {
   return LayoutUnit(getHostWindow()->windowToViewportScalar(1));
 }
 
 }  // namespace blink