Disconnect from WebScreenOrientationClient when frame is detached.

Source/modules/screen_orientation/ScreenOrientationController.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/screen_orientation/ScreenOrientationController.h"
 
 #include "core/events/Event.h"
 #include "core/frame/FrameView.h"
 #include "core/frame/LocalFrame.h"
@@ skipping 137 matching lines @@
 void ScreenOrientationController::setOrientation(ScreenOrientation* orientation)
 {
     m_orientation = orientation;
     if (m_orientation)
         updateOrientation();
     notifyDispatcher();
 }
 
 void ScreenOrientationController::lock(WebScreenOrientationLockType orientation, WebLockOrientationCallback* callback)
 {
-    ASSERT(m_client);
+    // When detached, the client is no longer valid.
+    if (!m_client)
+        return;
     m_client->lockOrientation(orientation, callback);
 }
 
 void ScreenOrientationController::unlock()
 {
-    ASSERT(m_client);
+    // When detached, the client is no longer valid.
+    if (!m_client)
+        return;
     m_client->unlockOrientation();
 }
 
 void ScreenOrientationController::dispatchEventTimerFired(Timer<ScreenOrientationController>*)
 {
     if (!m_orientation)
         return;
     m_orientation->dispatchEvent(Event::create(EventTypeNames::change));
 }
 
@@ skipping 10 matching lines @@
 void ScreenOrientationController::unregisterWithDispatcher()
 {
     ScreenOrientationDispatcher::instance().removeController(this);
 }
 
 bool ScreenOrientationController::hasLastData()
 {
     return true;
 }
 
+void ScreenOrientationController::willDetachFrameHost()
+{
+    m_client = nullptr;
+}
+
 void ScreenOrientationController::notifyDispatcher()
 {
     if (m_orientation && page()->visibilityState() == PageVisibilityStateVisible)
         startUpdating();
     else
         stopUpdating();
 }
 
 void ScreenOrientationController::trace(Visitor* visitor)
 {
     visitor->trace(m_orientation);
     FrameDestructionObserver::trace(visitor);
     WillBeHeapSupplement<LocalFrame>::trace(visitor);
     PlatformEventController::trace(visitor);
 }
 
 } // namespace blink