Pass implementation object to supplemental classes by reference

Source/modules/donottrack/NavigatorDoNotTrack.cpp

Index: Source/modules/donottrack/NavigatorDoNotTrack.cpp
diff --git a/Source/modules/donottrack/NavigatorDoNotTrack.cpp b/Source/modules/donottrack/NavigatorDoNotTrack.cpp
index 5358b2c93a8768056b2cce2eb724d53891cd339e..f8869dd31e0f20e5219d5e54a2812c066b3de9c7 100644
--- a/Source/modules/donottrack/NavigatorDoNotTrack.cpp
+++ b/Source/modules/donottrack/NavigatorDoNotTrack.cpp
@@ -51,19 +51,19 @@ const char* NavigatorDoNotTrack::supplementName()
     return "NavigatorDoNotTrack";
 }
 
-NavigatorDoNotTrack* NavigatorDoNotTrack::from(Navigator* navigator)
+NavigatorDoNotTrack& NavigatorDoNotTrack::from(Navigator& navigator)
 {
     NavigatorDoNotTrack* supplement = static_cast<NavigatorDoNotTrack*>(Supplement<Navigator>::from(navigator, supplementName()));
     if (!supplement) {
-        supplement = new NavigatorDoNotTrack(navigator->frame());
+        supplement = new NavigatorDoNotTrack(navigator.frame());
         provideTo(navigator, supplementName(), adoptPtr(supplement));
     }
-    return supplement;
+    return *supplement;
 }
 
-String NavigatorDoNotTrack::doNotTrack(Navigator* navigator)
+String NavigatorDoNotTrack::doNotTrack(Navigator& navigator)
 {
-    return NavigatorDoNotTrack::from(navigator)->doNotTrack();
+    return NavigatorDoNotTrack::from(navigator).doNotTrack();
 }
 
 String NavigatorDoNotTrack::doNotTrack()