Oilpan: Fix leaks through RenderStyle objects.

Source/core/fetch/ResourceFetcher.h

Index: Source/core/fetch/ResourceFetcher.h
diff --git a/Source/core/fetch/ResourceFetcher.h b/Source/core/fetch/ResourceFetcher.h
index 317ad9561009ea421ae874e502d18a7582b24cc7..95a154269394a2dbc805041852b11a09b1f7e610 100644
--- a/Source/core/fetch/ResourceFetcher.h
+++ b/Source/core/fetch/ResourceFetcher.h
@@ -205,7 +205,10 @@ private:
 
     HashSet<String> m_validatedURLs;
     mutable DocumentResourceMap m_documentResources;
-    RawPtrWillBeMember<Document> m_document;
+    // FIXME: Oilpan: Ideally this should just be a traced Member but that will
+    // currently leak because RenderStyle and its data are not on the heap.
+    // See crbug.com/383860 for details.
+    RawPtrWillBeWeakMember<Document> m_document;
     DocumentLoader* m_documentLoader;
 
     int m_requestCount;