Auto merge of #7498 - pcwalton:inline-absolute-containing-blocks, r=mbrubeck

layout: Implement partial support for inline absolute containing blocks.

Improves the position of the down arrows on google.com SERPs.

r? @mbrubeck

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components/layout/fragment.rs

@@ -2272,6 +2272,11 @@ impl Fragment {
         }
         false
     }
+
+    /// Returns true if this node is absolutely positioned.
+    pub fn is_absolutely_positioned(&self) -> bool {
+        self.style.get_box().position == position::T::absolute
+    }
 }
 
 impl fmt::Debug for Fragment {