Don't send loading completion callbacks for detaching frames.

third_party/WebKit/Source/core/loader/FrameLoader.cpp

Index: third_party/WebKit/Source/core/loader/FrameLoader.cpp
diff --git a/third_party/WebKit/Source/core/loader/FrameLoader.cpp b/third_party/WebKit/Source/core/loader/FrameLoader.cpp
index 83912c85c72ef76136a71665479b9a957ef579fc..5d8cb2ba585976a97ab18fb8bc36feea004f2068 100644
--- a/third_party/WebKit/Source/core/loader/FrameLoader.cpp
+++ b/third_party/WebKit/Source/core/loader/FrameLoader.cpp
@@ -671,6 +671,11 @@ static bool shouldSendFinishNotification(LocalFrame* frame) {
   // An event might have restarted a child frame.
   if (!allDescendantsAreComplete(frame))
     return false;
+
+  // Don't notify if the frame is being detached.
+  if (frame->isDetaching())
+    return false;
+
   return true;
 }