The mFinishedRequests / mTotalRequests counters in nsBrowserStatusFilter has been known buggy for around a decade. With e10s we double filtered in both parent and child processes which makes it worse. There are a few problems with the counters / filter: 1. The ResetMembers() were invoked on each network request starts, which means a iframe document loading followed by the root document loading would also reset the members incorrectly. 2. The filter for non-network request was incorrect. The basic idea seems to be that if `mFinishedRequests == mTotalRequests` and `!isLoadingDocument`, it should be the STOP request right after document loading finishes, and that STOP should be delivered so listener would get symmetric numbers of START / STOP of STATE_IS_REQUEST. However some requests such as imgRequest can start after document loading finishes, in this case the START would be filtered out (since mFinishedRequests != mTotalRequests), but STOP would be delivered to the listener. It's the reason that nsBrowserStatusFilter tend to deliver much more STATE_STOP than STATE_START. 3. When applying the filter on both parent & child side, the above issues often make the mFinishedRequests / mFinishedRequests be unmatched on parent side, eseentially filtered out most non-network requests and make the progressChange based on the counters useless. Firefox no longer shows the ratio of progressChange on the UI (and the number is incorrect anyway with current nsBrowserStatusFilter), and Fennec's progress bar is based on some predefined constants [1] which doesn't rely on progressChange either, so it not necessary to keep calculating a progress number with request counters. In addition, it seems tabbrowser & browser.js mostly only care about STATE_IS_NETWORK, and Fennec has already filtered out everything else [2], it should be safe to only pass STATE_IS_NETWORK to the listener, and we get the benefit of reducing unused IPC messages. [1] https://searchfox.org/mozilla-central/rev/9bab9dc5a9472e3c163ab279847d2249322c206e/mobile/android/base/java/org/mozilla/gecko/Tab.java#111-115 [2] https://searchfox.org/mozilla-central/rev/9bab9dc5a9472e3c163ab279847d2249322c206e/mobile/android/chrome/content/browser.js#4356-4357 Review commit: https://reviewboard.mozilla.org/r/200690/diff/#index_header See other reviews: https://reviewboard.mozilla.org/r/200690/

Comment on attachment 8929369 [details] Bug 1414745 - Filter out everything except STATE_IS_NETWORK in nsBrowserStatusFilter::OnStateChange. Review request updated; see interdiff: https://reviewboard.mozilla.org/r/200690/diff/1-2/