[Layout API] Use Document::layoutViewItem in WebFrameTest

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

Index: third_party/WebKit/Source/core/layout/api/LayoutItem.h
diff --git a/third_party/WebKit/Source/core/layout/api/LayoutItem.h b/third_party/WebKit/Source/core/layout/api/LayoutItem.h
index 0793caa1203000ff303d3d91a83e54f360ae9c1d..e9ea152423f75c09fc97c8626c3aa509d86acaa5 100644
--- a/third_party/WebKit/Source/core/layout/api/LayoutItem.h
+++ b/third_party/WebKit/Source/core/layout/api/LayoutItem.h
@@ -177,6 +177,11 @@ public:
         return m_layoutObject->styleRef();
     }
 
+    ComputedStyle& mutableStyleRef() const
+    {
+        return m_layoutObject->mutableStyleRef();
+    }
+
     LayoutSize offsetFromContainer(const LayoutItem& item) const
     {
         return m_layoutObject->offsetFromContainer(item.layoutObject());