Disconnect from WebScreenOrientationClient when frame is detached.

Source/modules/screen_orientation/ScreenOrientationController.cpp

Index: Source/modules/screen_orientation/ScreenOrientationController.cpp
diff --git a/Source/modules/screen_orientation/ScreenOrientationController.cpp b/Source/modules/screen_orientation/ScreenOrientationController.cpp
index 1c068bcd647e82b786134668b913f8a4797f99a8..6a354383f22bdb4b1e7969023375e74bb655d124 100644
--- a/Source/modules/screen_orientation/ScreenOrientationController.cpp
+++ b/Source/modules/screen_orientation/ScreenOrientationController.cpp
@@ -155,13 +155,17 @@ void ScreenOrientationController::setOrientation(ScreenOrientation* orientation)
 
 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+    // When detached, the client is no longer valid.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+    // When detached, the client is no longer valid.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();
 }
 
@@ -192,6 +196,11 @@ bool ScreenOrientationController::hasLastData()
     return true;
 }
 
+void ScreenOrientationController::willDetachFrameHost()
+{
+    m_client = nullptr;
+}
+
 void ScreenOrientationController::notifyDispatcher()
 {
     if (m_orientation && page()->visibilityState() == PageVisibilityStateVisible)