Move convertViewportToWindow and convertWindowToViewport from

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

Index: third_party/WebKit/Source/platform/scroll/ScrollableArea.cpp
diff --git a/third_party/WebKit/Source/platform/scroll/ScrollableArea.cpp b/third_party/WebKit/Source/platform/scroll/ScrollableArea.cpp
index fb47bcb35367065b311f3047fb28efdee9ad1c33..58eb3cb98edde32d6328bec49af3134370db8cf8 100644
--- a/third_party/WebKit/Source/platform/scroll/ScrollableArea.cpp
+++ b/third_party/WebKit/Source/platform/scroll/ScrollableArea.cpp
@@ -59,11 +59,11 @@ struct SameSizeAsScrollableArea {
 
 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(*widget, kPixelsPerLineStep);
 }
 
 float ScrollableArea::minFractionToStepWhenPaging()
@@ -134,7 +134,7 @@ ScrollbarOrientation ScrollableArea::scrollbarOrientationFromDirection(ScrollDir
     return (direction == ScrollUp  || direction == ScrollDown) ? VerticalScrollbar : HorizontalScrollbar;
 }
 
-float ScrollableArea::scrollStep(ScrollGranularity granularity, ScrollbarOrientation orientation) const
+float ScrollableArea::scrollStep(ScrollGranularity granularity, ScrollbarOrientation orientation)
 {
     switch (granularity) {
     case ScrollByLine:
@@ -567,9 +567,9 @@ DoublePoint ScrollableArea::clampScrollPosition(const DoublePoint& scrollPositio
     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