Oilpan: fix build after r201904.

Source/core/editing/EditingUtilitiesTest.cpp

Index: Source/core/editing/EditingUtilitiesTest.cpp
diff --git a/Source/core/editing/EditingUtilitiesTest.cpp b/Source/core/editing/EditingUtilitiesTest.cpp
index 3ce640cda1d81ce2b66cf45b5a9caae412ccc824..1fb902772901a64843779c72aea3317a2dd07764 100644
--- a/Source/core/editing/EditingUtilitiesTest.cpp
+++ b/Source/core/editing/EditingUtilitiesTest.cpp
@@ -84,7 +84,7 @@ TEST_F(EditingUtilitiesTest, isFirstPositionAfterTable)
     const char* bodyContent = "<div contenteditable id=host><table id=table><tr><td>1</td></tr></table><b id=two>22</b></div>";
     const char* shadowContent = "<content select=#two></content><content select=#table></content>";
     setBodyContent(bodyContent);
-    RefPtrWillBeRawPtr<ShadowRoot> shadowRoot = setShadowContent(shadowContent, "host");
+    setShadowContent(shadowContent, "host");
     updateLayoutAndStyleForPainting();
     Node* host = document().getElementById("host");
     Node* table = document().getElementById("table");