Pass implementation object to supplemental classes by reference

Source/modules/device_orientation/DeviceMotionController.cpp

Index: Source/modules/device_orientation/DeviceMotionController.cpp
diff --git a/Source/modules/device_orientation/DeviceMotionController.cpp b/Source/modules/device_orientation/DeviceMotionController.cpp
index 877fe372663d6bf364aec4779e3b23b7ee74a48e..9aec05c77e4127be9988516f2b230b3f4e1042e1 100644
--- a/Source/modules/device_orientation/DeviceMotionController.cpp
+++ b/Source/modules/device_orientation/DeviceMotionController.cpp
@@ -37,9 +37,9 @@
 
 namespace WebCore {
 
-DeviceMotionController::DeviceMotionController(Document* document)
+DeviceMotionController::DeviceMotionController(Document& document)
     : DeviceSensorEventController(document)
-    , DOMWindowLifecycleObserver(document->domWindow())
+    , DOMWindowLifecycleObserver(document.domWindow())
 {
 }
 
@@ -58,14 +58,14 @@ const char* DeviceMotionController::supplementName()
     return "DeviceMotionController";
 }
 
-DeviceMotionController* DeviceMotionController::from(Document* document)
+DeviceMotionController& DeviceMotionController::from(Document& document)
 {
     DeviceMotionController* controller = static_cast<DeviceMotionController*>(DocumentSupplement::from(document, supplementName()));
     if (!controller) {
         controller = new DeviceMotionController(document);
         DocumentSupplement::provideTo(document, supplementName(), adoptPtr(controller));
     }
-    return controller;
+    return *controller;
 }
 
 bool DeviceMotionController::hasLastData()