CLOSED TREE
Backed out changeset e716d9ac93d7 (bug 1214148)
Backed out changeset 5f693237c8c1 (bug 1214148)
Backed out changeset 3a4865d79416 (bug 1214148)
For top-level navigations, we need to compute the client ID when we decide to
intercept the document load, and we need to make sure the document that will
be created later will end up using that same ID.
Having this event means that we don't have to wait for content to find out whether it's scrollable in the case that no swipe should be happening anyway.
IGNORE IDL because I'm only changing comments in the IDL files.
--HG--
extra : commitid : 22814fSLcIz
extra : rebase_source : e51b4db26333275c9bcb3fd7fece78b7d3653275
Use counter submission normally happens at document destruction. For
testing use counters, however, we need to have use counters updated in
telemetry at deterministic points. Therefore, we provide a method on
nsIDOMWindowUtils that forces use counters out to telemetry so we can
examine them.
This is motivated by three separate but related problems:
1. Our concept of recursion depth is broken for things that run from AfterProcessNextEvent observers (e.g. Promises). We decrement the recursionDepth counter before firing observers, so a Promise callback running at the lowest event loop depth has a recursion depth of 0 (whereas a regular nsIRunnable would be 1). This is a problem because it's impossible to distinguish a Promise running after a sync XHR's onreadystatechange handler from a top-level event (since the former runs with depth 2 - 1 = 1, and the latter runs with just 1).
2. The nsIThreadObserver mechanism that is used by a lot of code to run "after" the current event is a poor fit for anything that runs script. First, the order the observers fire in is the order they were added, not anything fixed by spec. Additionally, running script can cause the event loop to spin, which is a big source of pain here (bholley has some nasty bug caused by this).
3. We run Promises from different points in the code for workers and main thread. The latter runs from XPConnect's nsIThreadObserver callbacks, while the former runs from a hardcoded call to run Promises in the worker event loop. What workers do is particularly problematic because it means we can't get the right recursion depth no matter what we do to nsThread.
The solve this, this patch does the following:
1. Consolidate some handling of microtasks and all handling of stable state from appshell and WorkerPrivate into CycleCollectedJSRuntime.
2. Make the recursionDepth counter only available to CycleCollectedJSRuntime (and its consumers) and remove it from the nsIThreadInternal and nsIThreadObserver APIs.
3. Adjust the recursionDepth counter so that microtasks run with the recursionDepth of the task they are associated with.
4. Introduce the concept of metastable state to replace appshell's RunBeforeNextEvent. Metastable state is reached after every microtask or task is completed. This provides the semantics that bent and I want for IndexedDB, where transactions autocommit at the end of a microtask and do not "spill" from one microtask into a subsequent microtask. This differs from appshell's RunBeforeNextEvent in two ways:
a) It fires between microtasks, which was the motivation for starting this.
b) It no longer ensures that we're at the same event loop depth in the native event queue. bent decided we don't care about this.
5. Reorder stable state to happen after microtasks such as Promises, per HTML. Right now we call the regular thread observers, including appshell, before the main thread observer (XPConnect), so stable state tasks happen before microtasks.
Randall Barker
Ben Kelly
Xidorn Quan
Andrea Marchesini
Carsten "Tomcat" Book
Alexandre Poirot
Phil Ringnalda
Ehsan Akhgari
Eddy Bruel
Gijs Kruitbosch
Bill McCloskey
Botond Ballo
George Wright
dlee
Kyle Huey
Bobby Holley
Catalin Badea
Wes Kocher
Nigel Babu
Kit Cambridge
Jim Mathies
Kartikaya Gupta
Markus Stange
Masayuki Nakano
Tim Chien
Ryan VanderMeulen
Benoit Girard
Nathan Froyd
Matt Woodrow
Brad Lassey