Bug 1450874 P2 Don't save service worker time stamps if the fetch event didn't actually dispatch. r=asuth

netwerk/protocol/http/InterceptedChannel.cpp

@@ -137,6 +137,12 @@ InterceptedChannelBase::SaveTimeStamps()
 {
   MOZ_ASSERT(NS_IsMainThread());
 
+  // If we were not able to start the fetch event for some reason (like
+  // corrupted scripts), then just do nothing here.
+  if (mHandleFetchEventStart.IsNull()) {
+    return NS_OK;
+  }
+
   nsCOMPtr<nsIChannel> underlyingChannel;
   nsresult rv = GetChannel(getter_AddRefs(underlyingChannel));
   MOZ_ASSERT(NS_SUCCEEDED(rv));

netwerk/protocol/http/InterceptedHttpChannel.cpp

@@ -957,6 +957,12 @@ InterceptedHttpChannel::SetChannelResetEnd(mozilla::TimeStamp aTimeStamp)
 NS_IMETHODIMP
 InterceptedHttpChannel::SaveTimeStamps(void)
 {
+  // If we were not able to start the fetch event for some reason (like
+  // corrupted scripts), then just do nothing here.
+  if (mHandleFetchEventStart.IsNull()) {
+    return NS_OK;
+  }
+
   bool isNonSubresourceRequest = nsContentUtils::IsNonSubresourceRequest(this);
   nsCString navigationOrSubresource = isNonSubresourceRequest ?
     NS_LITERAL_CSTRING("navigation") : NS_LITERAL_CSTRING("subresource");