Move convertViewportToWindow and convertWindowToViewport from

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

 /*
  * Copyright (c) 2010, Google Inc. All rights reserved.
  * Copyright (C) 2008, 2011 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 41 matching lines @@
 #if ENABLE(ASSERT)
     VerifyEagerFinalization verifyEager;
 #endif
     Member<void*> pointer[2];
     unsigned bitfields : 16;
     IntPoint origin;
 };
 
 static_assert(sizeof(ScrollableArea) == sizeof(SameSizeAsScrollableArea), "ScrollableArea should stay small");
 
-int ScrollableArea::pixelsPerLineStep(HostWindow* host)
+int ScrollableArea::pixelsPerLineStep(HostWindow* host, Widget* widget)
 {
     if (!host)
         return kPixelsPerLineStep;
-    return host->windowToViewportScalar(kPixelsPerLineStep);
+    return host->windowToViewportScalar(kPixelsPerLineStep, widget);
 }
 
 float ScrollableArea::minFractionToStepWhenPaging()
 {
     return kMinFractionToStepWhenPaging;
 }
 
 int ScrollableArea::maxOverlapBetweenPages()
 {
     static int maxOverlapBetweenPages = ScrollbarTheme::theme().maxOverlapBetweenPages();
@@ skipping 50 matching lines @@
 GraphicsLayer* ScrollableArea::layerForContainer() const
 {
     return layerForScrolling() ? layerForScrolling()->parent() : 0;
 }
 
 ScrollbarOrientation ScrollableArea::scrollbarOrientationFromDirection(ScrollDirectionPhysical direction) const
 {
     return (direction == ScrollUp  || direction == ScrollDown) ? VerticalScrollbar : HorizontalScrollbar;
 }
 
-float ScrollableArea::scrollStep(ScrollGranularity granularity, ScrollbarOrientation orientation) const
+float ScrollableArea::scrollStep(ScrollGranularity granularity, ScrollbarOrientation orientation)

[dcheng, 2016/09/08 05:25:47]

Argh const-correctness.

Let's just mark getWidget() const =(

[lfg, 2016/09/08 21:40:43]

I tried that before, but FrameView::getWidget returns "this", so it can't be
const.

 {
     switch (granularity) {
     case ScrollByLine:
         return lineStep(orientation);
     case ScrollByPage:
         return pageStep(orientation);
     case ScrollByDocument:
         return documentStep(orientation);
     case ScrollByPixel:
     case ScrollByPrecisePixel:
@@ skipping 412 matching lines @@
 IntPoint ScrollableArea::clampScrollPosition(const IntPoint& scrollPosition) const
 {
     return scrollPosition.shrunkTo(maximumScrollPosition()).expandedTo(minimumScrollPosition());
 }
 
 DoublePoint ScrollableArea::clampScrollPosition(const DoublePoint& scrollPosition) const
 {
     return scrollPosition.shrunkTo(maximumScrollPositionDouble()).expandedTo(minimumScrollPositionDouble());
 }
 
-int ScrollableArea::lineStep(ScrollbarOrientation) const
+int ScrollableArea::lineStep(ScrollbarOrientation)
 {
-    return pixelsPerLineStep(getHostWindow());
+    return pixelsPerLineStep(getHostWindow(), getWidget());
 }
 
 int ScrollableArea::pageStep(ScrollbarOrientation orientation) const
 {
     IntRect visibleRect = visibleContentRect(IncludeScrollbars);
     int length = (orientation == HorizontalScrollbar) ? visibleRect.width() : visibleRect.height();
     int minPageStep = static_cast<float>(length) * minFractionToStepWhenPaging();
     int pageStep = std::max(minPageStep, length - maxOverlapBetweenPages());
 
     return std::max(pageStep, 1);
@@ skipping 29 matching lines @@
         std::max(0, size.height() - horizontalScrollbarHeight()));
 }
 
 DEFINE_TRACE(ScrollableArea)
 {
     visitor->trace(m_scrollAnimator);
     visitor->trace(m_programmaticScrollAnimator);
 }
 
 } // namespace blink