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 fde5f299ac1e539ba4f62f6f845d6b91866f77a7..ae61e243062602d65311cd2e2b0c1b910856aeeb 100644
--- a/third_party/WebKit/Source/core/loader/FrameLoader.cpp
+++ b/third_party/WebKit/Source/core/loader/FrameLoader.cpp
@@ -687,6 +687,11 @@ 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;
 }