[Oilpan]: Move CSSFontSelectorClient to the oilpan heap using transition types.

Source/core/dom/StyleEngine.h

Index: Source/core/dom/StyleEngine.h
diff --git a/Source/core/dom/StyleEngine.h b/Source/core/dom/StyleEngine.h
index dc6940a39ac08fed4456d34f91c1354e1ec2fd7b..ea16b9e78d938221c3775b08e1555a881277ed9f 100644
--- a/Source/core/dom/StyleEngine.h
+++ b/Source/core/dom/StyleEngine.h
@@ -243,12 +243,12 @@ private:
 
     bool m_ignorePendingStylesheets;
     bool m_didCalculateResolver;
-    OwnPtr<StyleResolver> m_resolver;
+    OwnPtrWillBeMember<StyleResolver> m_resolver;
 
     RefPtr<CSSFontSelector> m_fontSelector;
 
-    HashMap<AtomicString, StyleSheetContents*> m_textToSheetCache;
-    HashMap<StyleSheetContents*, AtomicString> m_sheetToTextCache;
+    WillBeHeapHashMap<AtomicString, RawPtrWillBeMember<StyleSheetContents> > m_textToSheetCache;
+    WillBeHeapHashMap<RawPtrWillBeMember<StyleSheetContents>, AtomicString> m_sheetToTextCache;
 };
 
 }