ScrollableArea::pixelsPerLine should return viewport pixels in use-zoom-for-dsf mode

third_party/WebKit/Source/platform/scroll/Scrollbar.cpp

 /*
  * Copyright (C) 2004, 2006, 2008 Apple Inc. All rights reserved.
  *
  * 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
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 64 matching lines @@
     , m_trackNeedsRepaint(true)
     , m_thumbNeedsRepaint(true)
 {
     m_theme.registerScrollbar(*this);
 
     // FIXME: This is ugly and would not be necessary if we fix cross-platform code to actually query for
     // scrollbar thickness and use it when sizing scrollbars (rather than leaving one dimension of the scrollbar
     // alone when sizing).
     int thickness = m_theme.scrollbarThickness(controlSize);
     if (m_hostWindow)
-        thickness = m_hostWindow->windowToViewport(FloatRect(0, 0, thickness, 0)).width();
+        thickness = m_hostWindow->windowToViewportScalar(thickness);
     Widget::setFrameRect(IntRect(0, 0, thickness, thickness));
 
     m_currentPos = scrollableAreaCurrentPos();
 }
 
 Scrollbar::~Scrollbar()
 {
     m_theme.unregisterScrollbar(*this);
 }
 
@@ skipping 380 matching lines @@
     m_enabled = e;
     theme().updateEnabledState(*this);
     setNeedsPaintInvalidation(AllParts);
 }
 
 int Scrollbar::scrollbarThickness() const
 {
     int thickness = orientation() == HorizontalScrollbar ? height() : width();
     if (!thickness || !m_hostWindow)
         return thickness;
-    return m_hostWindow->windowToViewport(FloatRect(0, 0, m_theme.scrollbarThickness(controlSize()), 0)).width();
+    return m_hostWindow->windowToViewportScalar(m_theme.scrollbarThickness(controlSize()));
 }
 
 
 bool Scrollbar::isOverlayScrollbar() const
 {
     return m_theme.usesOverlayScrollbars();
 }
 
 bool Scrollbar::shouldParticipateInHitTesting()
 {
@@ skipping 83 matching lines @@
         invalidParts = AllParts;
     if (invalidParts & ~ThumbPart)
         m_trackNeedsRepaint = true;
     if (invalidParts & ThumbPart)
         m_thumbNeedsRepaint = true;
     if (m_scrollableArea)
         m_scrollableArea->setScrollbarNeedsPaintInvalidation(orientation());
 }
 
 } // namespace blink