Bug 2166879

Description of problem:

I detected a "loop of death" inside firefox+DE, which can OOM firefox with a possible crash in the end.

Of course this is a level 8 problem, as the user selects this. The real bug is, that ff offers itself as the app to handle this. This should not happen.

Additionally, FF does not seem to detect, that it is inside this loop of opening files via the DEs Default App function. I suggest to add one, as this leeds to OOM (takes a while), crash&db-corruption(due to oom) and waste of diskspace (partfile entries). 

In my test, i stopped it at 453 tabs + partfiles :)

Version-Release number of selected component (if applicable):

ALL

How reproducible:

easy.

Opening an MD file, like Readme.md, with firefox.


Steps to Reproduce:

1. Find a Markdown file
2. open it with firefox
3. Firefox offers to download that md file ( pre-selected ) or to open it in an App. Select firefox. Loop closed.

Now we have a loop of opening tabs on our hands, which produces PART Files in the userhome:

-rw-------. 1 username username 0  3. Feb 11:10 WFNDAxzY.part
-rw-------. 1 username username 0  3. Feb 11:10 wjf954Ez.part
-rw-------. 1 username username 0  3. Feb 11:10 wKlezHso.part
-rw-------. 1 username username 0  3. Feb 11:11 wMpPLySE.part
-rw-------. 1 username username 0  3. Feb 11:10 WpxVeW8E.part
-rw-------. 1 username username 0  3. Feb 11:10 wQOo8Du2.part
-rw-------. 1 username username 0  3. Feb 11:10 wtPT_gBB.part
-rw-------. 1 username username 0  3. Feb 11:10 WvxNyIlJ.part
-rw-------. 1 username username 0  3. Feb 11:10 wVXwqzS9.part
-rw-------. 1 username username 0  3. Feb 11:10 WxinqAhW.part
-rw-------. 1 username username 0  3. Feb 11:10 -wXmm0fo.part
-rw-------. 1 username username 0  3. Feb 11:10 wZsHjXgz.part
-rw-------. 1 username username 0  3. Feb 11:10 X8uzLaFy.part
-rw-------. 1 username username 0  3. Feb 11:10 xczNf5T_.part
-rw-------. 1 username username 0  3. Feb 11:10 Xd8d8zjF.part
-rw-------. 1 username username 0  3. Feb 11:10 xd-rAjTh.part
-rw-------. 1 username username 0  3. Feb 11:10 xHA9FPof.part
-rw-------. 1 username username 0  3. Feb 11:11 XiwxZ6Lr.part
-rw-------. 1 username username 0  3. Feb 11:10 xIY7YT6p.part
-rw-------. 1 username username 0  3. Feb 11:10 XOjfitdK.part
-rw-------. 1 username username 0  3. Feb 11:10 XOLeojyL.part
-rw-------. 1 username username 0  3. Feb 11:10 xoxbEngL.part
-rw-------. 1 username username 0  3. Feb 11:10 XpFmDscK.part
-rw-------. 1 username username 0  3. Feb 11:10 xPqzoCDy.part
-rw-------. 1 username username 0  3. Feb 11:10 XsqD-MxM.part
-rw-------. 1 username username 0  3. Feb 11:10 Xt_EQNsx.part
-rw-------. 1 username username 0  3. Feb 11:10 XyHDZfcv.part
-rw-------. 1 username username 0  3. Feb 11:10 xYlPzOcg.part
-rw-------. 1 username username 0  3. Feb 11:10 Xyz8MFoB.part
-rw-------. 1 username username 0  3. Feb 11:10 Y0793--B.part
-rw-------. 1 username username 0  3. Feb 11:11 Y33prt5r.part
-rw-------. 1 username username 0  3. Feb 11:10 Y3n4Jlao.part
-rw-------. 1 username username 0  3. Feb 11:10 y5gqxvp-.part
-rw-------. 1 username username 0  3. Feb 11:10 y7BJ7rr3.part
-rw-------. 1 username username 0  3. Feb 11:10 Y7D6kAdU.part
-rw-------. 1 username username 0  3. Feb 11:10 y7QlpRyx.part
-rw-------. 1 username username 0  3. Feb 11:11 YclFs4fm.part
-rw-------. 1 username username 0  3. Feb 11:11 ygSiiVET.part
-rw-------. 1 username username 0  3. Feb 11:10 yiWa5DWq.part
-rw-------. 1 username username 0  3. Feb 11:11 YM7AnK4R.part
-rw-------. 1 username username 0  3. Feb 11:10 yMS61vWE.part
-rw-------. 1 username username 0  3. Feb 11:10 _Yprvz6d.part
-rw-------. 1 username username 0  3. Feb 11:11 YPSOm_ZN.part
-rw-------. 1 username username 0  3. Feb 11:10 Y-sao3NZ.part
-rw-------. 1 username username 0  3. Feb 11:10 ysW8XkfW.part
-rw-------. 1 username username 0  3. Feb 11:10 yuFleI0H.part
-rw-------. 1 username username 0  3. Feb 11:10 yUSdxFSK.part
-rw-------. 1 username username 0  3. Feb 11:10 yXyvb-rp.part
-rw-------. 1 username username 0  3. Feb 11:11 yzrvwC1B.part
-rw-------. 1 username username 0  3. Feb 11:10 z9vRmjrj.part
-rw-------. 1 username username 0  3. Feb 11:10 ZehVT_gf.part
-rw-------. 1 username username 0  3. Feb 11:10 ZfILuE4u.part
-rw-------. 1 username username 0  3. Feb 11:10 zgyhWqXf.part
-rw-------. 1 username username 0  3. Feb 11:10 ZHUcPSoX.part
-rw-------. 1 username username 0  3. Feb 11:10 zlexJF1a.part
-rw-------. 1 username username 0  3. Feb 11:10 z_NFNQjP.part
-rw-------. 1 username username 0  3. Feb 11:10 zuAd-gQ4.part
-rw-------. 1 username username 0  3. Feb 11:10 ZvkM9XCi.part
-rw-------. 1 username username 0  3. Feb 11:10 zvvUbOD_.part
-rw-------. 1 username username 0  3. Feb 11:11 zVXxj9Tz.part
-rw-------. 1 username username 0  3. Feb 11:11 zxmOuI3i.part
-rw-------. 1 username username 0  3. Feb 11:10 zY8ReQS4.part
-rw-------. 1 username username 0  3. Feb 11:11 _ZzGApIf.part