Pass implementation object to supplemental classes by reference

Source/modules/device_orientation/DeviceOrientationInspectorAgent.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "modules/device_orientation/DeviceOrientationInspectorAgent.h"
 
 #include "core/dom/Document.h"
 #include "core/frame/Frame.h"
 #include "core/inspector/InspectorController.h"
 #include "core/page/Page.h"
 
 #include "modules/device_orientation/DeviceOrientationController.h"
 #include "modules/device_orientation/DeviceOrientationData.h"
 
 namespace WebCore {
 
-void DeviceOrientationInspectorAgent::provideTo(Page* page)
+void DeviceOrientationInspectorAgent::provideTo(Page& page)
 {
     OwnPtr<DeviceOrientationInspectorAgent> deviceOrientationAgent(adoptPtr(new DeviceOrientationInspectorAgent(page)));
-    page->inspectorController().registerModuleAgent(deviceOrientationAgent.release());
+    page.inspectorController().registerModuleAgent(deviceOrientationAgent.release());
 }
 
 DeviceOrientationInspectorAgent::~DeviceOrientationInspectorAgent()
 {
 }
 
-DeviceOrientationInspectorAgent::DeviceOrientationInspectorAgent(Page* page)
+DeviceOrientationInspectorAgent::DeviceOrientationInspectorAgent(Page& page)
     : InspectorBaseAgent<DeviceOrientationInspectorAgent>("DeviceOrientation")
     , m_page(page)
 {
 }
 
 void DeviceOrientationInspectorAgent::setDeviceOrientationOverride(ErrorString* error, double alpha, double beta, double gamma)
 {
-    DeviceOrientationController* controller = DeviceOrientationController::from(m_page->mainFrame()->document());
-    if (!controller) {
-        *error = "Internal error: unable to override device orientation";
-        return;
-    }
-    controller->didChangeDeviceOrientation(DeviceOrientationData::create(true, alpha, true, beta, true, gamma).get());
+    ASSERT(m_page.mainFrame()->document());
+    DeviceOrientationController& controller = DeviceOrientationController::from(*m_page.mainFrame()->document());
+    controller.didChangeDeviceOrientation(DeviceOrientationData::create(true, alpha, true, beta, true, gamma).get());
 }
 
 void DeviceOrientationInspectorAgent::clearDeviceOrientationOverride(ErrorString* error)
 {
     setDeviceOrientationOverride(error, 0, 0, 0);
 }
 
 } // namespace WebCore