[Layout API] Use Document::layoutViewItem() in ViewportStyleResolver

third_party/WebKit/Source/core/layout/api/LayoutViewItem.h

Index: third_party/WebKit/Source/core/layout/api/LayoutViewItem.h
diff --git a/third_party/WebKit/Source/core/layout/api/LayoutViewItem.h b/third_party/WebKit/Source/core/layout/api/LayoutViewItem.h
index ede8d154744c09867e4ab05049f6189b7b93a7c6..c9cc45678a13a7bbb8c6ac81deab05dcad30f27e 100644
--- a/third_party/WebKit/Source/core/layout/api/LayoutViewItem.h
+++ b/third_party/WebKit/Source/core/layout/api/LayoutViewItem.h
@@ -128,6 +128,11 @@ public:
         return toView()->viewWidth(scrollbarInclusion);
     }
 
+    FloatSize viewportSizeForViewportUnits() const
+    {
+        return toView()->viewportSizeForViewportUnits();
+    }
+
 private:
     LayoutView* toView() { return toLayoutView(layoutObject()); }
     const LayoutView* toView() const { return toLayoutView(layoutObject()); }