Make scrollWidth and scrollHeight match other DOM measurement APIs

Source/web/WebViewImpl.cpp

Index: Source/web/WebViewImpl.cpp
diff --git a/Source/web/WebViewImpl.cpp b/Source/web/WebViewImpl.cpp
index 30a4a43100e1847891cc95728ebfc689c1ad513f..a19ee0115a8fd9e8959551635bda867dcfd28018 100644
--- a/Source/web/WebViewImpl.cpp
+++ b/Source/web/WebViewImpl.cpp
@@ -3364,12 +3364,14 @@ IntSize WebViewImpl::contentsSize() const
 WebSize WebViewImpl::contentsPreferredMinimumSize()
 {
     Document* document = m_page->mainFrame()->isLocalFrame() ? m_page->deprecatedLocalMainFrame()->document() : 0;
-    if (!document || !document->layoutView() || !document->documentElement())
+    if (!document || !document->layoutView() || !document->documentElement() || !document->documentElement()->layoutBox())
         return WebSize();
 
     layout();
     int widthScaled = document->layoutView()->minPreferredLogicalWidth(); // Already accounts for zoom.
-    int heightScaled = static_cast<int>(document->documentElement()->scrollHeight() * zoomLevelToZoomFactor(zoomLevel()));
+    LayoutBox* documentBox = document->documentElement()->layoutBox();
+    // We truncate then zoom the height instead of rounding to match the width behavior.

[pdr., 2015/03/26 20:19:36]

Can you add a fixme and file a separate bug for this?

+    int heightScaled = adjustLayoutUnitForAbsoluteZoom(documentBox->scrollHeight(), *documentBox).toInt() * zoomLevelToZoomFactor(zoomLevel());
     return IntSize(widthScaled, heightScaled);
 }