Remove forward declarations from Source/core/dom/custom

Source/core/dom/custom/CustomElementObserver.h

Index: Source/core/dom/custom/CustomElementObserver.h
diff --git a/Source/core/dom/custom/CustomElementObserver.h b/Source/core/dom/custom/CustomElementObserver.h
index 582e3e9b602edcb2ab51d431738ca9588d95b093..3a48d755ddfa9039d0be8dad21ed078e15495cc1 100644
--- a/Source/core/dom/custom/CustomElementObserver.h
+++ b/Source/core/dom/custom/CustomElementObserver.h
@@ -43,7 +43,6 @@ public:
     virtual ~CustomElementObserver() { }
 
     // API for CustomElement to kick off notifications
-
     static void notifyElementDidFinishParsingChildren(Element*);
     static void notifyElementWasDestroyed(Element*);
 
@@ -59,6 +58,6 @@ protected:
     virtual void elementWasDestroyed(Element* element) { unobserve(element); }
 };
 
-}
+} // namespace blink
 
 #endif // CustomElementObserver_h