documentStyleSheetCollection() is always non-null.

third_party/WebKit/Source/core/dom/StyleEngine.h

Index: third_party/WebKit/Source/core/dom/StyleEngine.h
diff --git a/third_party/WebKit/Source/core/dom/StyleEngine.h b/third_party/WebKit/Source/core/dom/StyleEngine.h
index 132c3c1796aa30345f3a844ded4cbf69dee2a157..b6323caf35a0ea44cf0fb16ed534be43ace5ac51 100644
--- a/third_party/WebKit/Source/core/dom/StyleEngine.h
+++ b/third_party/WebKit/Source/core/dom/StyleEngine.h
@@ -255,12 +255,14 @@ class CORE_EXPORT StyleEngine final
                             const String& text,
                             TextPosition startPosition);
 
-  const DocumentStyleSheetCollection* documentStyleSheetCollection() const {
-    return m_documentStyleSheetCollection.get();
+  const DocumentStyleSheetCollection& documentStyleSheetCollection() const {
+    DCHECK(m_documentStyleSheetCollection.get());
+    return *m_documentStyleSheetCollection.get();

[meade_UTC10, 2016/10/11 05:53:24]

The .get seems redundant - can this just be 

DCHECK(m_documentStyleSheetCollection);
return *m_documentStyleSheetCollection;

?

[rune, 2016/10/12 09:19:19]

Done.

   }
 
-  DocumentStyleSheetCollection* documentStyleSheetCollection() {
-    return m_documentStyleSheetCollection.get();
+  DocumentStyleSheetCollection& documentStyleSheetCollection() {
+    DCHECK(m_documentStyleSheetCollection.get());
+    return *m_documentStyleSheetCollection.get();
   }
 
   void updateActiveStyleSheetsInShadow(