Fix crash when an onorientationchange event detaches an iframe.

Source/web/tests/WebFrameTest.cpp

Index: Source/web/tests/WebFrameTest.cpp
diff --git a/Source/web/tests/WebFrameTest.cpp b/Source/web/tests/WebFrameTest.cpp
index a8c8b22ba93b3a724f0bee68b1e325ceed65fb62..4ba5c6abac73a93313e60c7177fdb4f04f4f4ab2 100644
--- a/Source/web/tests/WebFrameTest.cpp
+++ b/Source/web/tests/WebFrameTest.cpp
@@ -7718,4 +7718,13 @@ TEST_F(WebFrameOverscrollTest, ScaledPageRootLayerOverscrolled)
     Mock::VerifyAndClearExpectations(&client);
 }
 
+TEST_F(WebFrameTest, OrientationFrameDetach)
+{
+    RuntimeEnabledFeatures::setOrientationEventEnabled(true);
+    registerMockedHttpURLLoad("orientation-frame-detach.html");
+    FrameTestHelpers::WebViewHelper webViewHelper;
+    WebViewImpl* webViewImpl = webViewHelper.initializeAndLoad(m_baseURL + "orientation-frame-detach.html", true);
+    webViewImpl->mainFrameImpl()->sendOrientationChangeEvent();
+}
+
 } // namespace blink