Don't change layout size due to top control show/hide

third_party/WebKit/Source/core/layout/LayoutView.cpp

Index: third_party/WebKit/Source/core/layout/LayoutView.cpp
diff --git a/third_party/WebKit/Source/core/layout/LayoutView.cpp b/third_party/WebKit/Source/core/layout/LayoutView.cpp
index b84eba735d75a2a6988cb780a05e42b83bef8dd4..c4b1ab4b43979500ab67df76d3b70c6c1ef047f3 100644
--- a/third_party/WebKit/Source/core/layout/LayoutView.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutView.cpp
@@ -962,16 +962,9 @@ bool LayoutView::backgroundIsKnownToBeOpaqueInRect(const LayoutRect&) const
     return m_frameView->hasOpaqueBackground();
 }
 
-double LayoutView::layoutViewportWidth() const
+FloatSize LayoutView::viewportSizeForViewportUnits() const
 {
-    float scale = m_frameView ? m_frameView->frame().pageZoomFactor() : 1;

[jbroman, 2016/01/20 15:44:28]

Do you know why this null check was here before? Is it possible for frameView()
to be null?

[bokan, 2016/01/20 16:41:10]

I removed it since lots of surrounding code wasn't checking and assumed it is
set. Looking through how m_frameView is initialized, it looks like in the common
case it should be non-null but I now see some XSLT path that may not have a
frame? Anyway, I put the check back in, just in case.

-    return viewWidth(IncludeScrollbars) / scale;
-}
-
-double LayoutView::layoutViewportHeight() const
-{
-    float scale = m_frameView ? m_frameView->frame().pageZoomFactor() : 1;
-    return viewHeight(IncludeScrollbars) / scale;
+    return frameView()->viewportSizeForViewportUnits();
 }
 
 void LayoutView::willBeDestroyed()