This patch makes several fundamental changes to the logic we use to inform
the main process whenever the WER runtime exception module intercepts a child
process crash:

* We no longer read the process type or any other data from the child process;
  the process type is passed as the runtime exception module's context
* We no longer read the address of the memory area used to communicate with the
  main process from the child process arguments. Instead we allocate memory
  directly into the main process and store the required information there
* We don't read anything from the main process either, the pointer to the
  function used to notify the main process is now found by looking out its
  dedicated section in the parent process' xul.dll mapping
* We no longer read the OOM crash annotation from a child process, this
  functionality will be restored by making the module use the mozannotation
  crates to fetch all the annotations

Original Revision: https://phabricator.services.mozilla.com/D201589

Differential Revision: https://phabricator.services.mozilla.com/D202916

Bug 1851989 - Add checks in BackgroundParentImpl to see if methods are called by correct actors, r=nika a=pascalc

Differential Revision: https://phabricator.services.mozilla.com/D187785

Bug 1845146 - Check numberOfBytes{Read,Written} in TestManyHandles, r=ipc-reviewers,handyman a=test-only

When running GTests on Windows 7, the TestManyHandles test crashes due
to the lpNumberOfBytesWritten argument to WriteFile not being passed.
This argument is required on earlier versions of Windows like Windows 7.

While we no longer support Windows 7 on Nightly, we still support it on
ESR, and are trying to run GTests on Windows 7 there. It also doesn't
hurt to add extra assertions that the full amount of data is
read/written, so checking this could be valuable on m-c as well.

Differential Revision: https://phabricator.services.mozilla.com/D184393

Differential Revision: https://phabricator.services.mozilla.com/D181196

Bug 1826869 - Cache doc mime type and make available via DocAccessibleParent. r=morgan,ipc-reviewers,mccr8

Differential Revision: https://phabricator.services.mozilla.com/D178887

Differential Revision: https://phabricator.services.mozilla.com/D178886

Bug 1821965 - P2: Remove sync IPC extension messages for text operations. r=morgan,ipc-reviewers,mccr8

We can get rid the entire local HyperTextAccessible-based implementation as well!

Depends on D178717

Differential Revision: https://phabricator.services.mozilla.com/D178718

Depends on D178715

Differential Revision: https://phabricator.services.mozilla.com/D178724

This patch changes KillHard() such that the IPC channel is immediately
shut down with an error after a KillHard() is performed. This is done by
fixing the previously-broken CLOSE_CHANNEL_WITH_ERROR support in
ShutDownProcess, and calling that method after KillHard().

This ensures that after the process has been killed, no further messages
will be delivered and processed, even if they were sent before the
process was killed.

In addition, the assertions and KillHard calls which are disabled for
fuzzing were changed to also shut down the channel, making fuzzing IPC
errors cause the connection to be terminated like it is in production
for these actors.

This change does not impact actors which ignore processing errors.

Differential Revision: https://phabricator.services.mozilla.com/D178383

This refactoring cleans up some dead code, and makes some semantic
changes to how the MessageChannel lifecycle is handled.

These changes ensure that messages which were sent by a peer before the
GOODBYE message will be delivered, without allowing messages sent after
the GOODBYE message (e.g. by a misbehaving process) to be delivered.

The lifecycle and shutdown states were simplified, and moved to be
entirely in MessageChannel, rather than split between MessageChannel and
MessageLink.

The dead-code ChannelTimeout error state was removed, along with the
corresponding CloseWithTimeout method.

The CloseWithError method was updated to behave more consistently with
the normal Close method, synchronously triggering a connection error,
and closing the MessageLink. This method is currently unused, but will
useful in the future for handling processing errors.

Differential Revision: https://phabricator.services.mozilla.com/D178382

Backed out changeset 6df0877f288a (bug 1821965)
Backed out changeset e663ccc0334e (bug 1821965)
Backed out changeset 36b250225e50 (bug 1821965)
Backed out changeset 6df5d07bf19f (bug 1832353)
Backed out changeset 409966c76f0f (bug 1832353)
Backed out changeset 3be446e44436 (bug 1832353)

Bug 1821965 - P2: Remove sync IPC extension messages for text operations. r=morgan,ipc-reviewers,mccr8

We can get rid the entire local HyperTextAccessible-based implementation as well!

Depends on D178717

Differential Revision: https://phabricator.services.mozilla.com/D178718

Differential Revision: https://phabricator.services.mozilla.com/D178724

Differential Revision: https://phabricator.services.mozilla.com/D178976

MessagePump_mac.mm is built for Darwin.

Differential Revision: https://phabricator.services.mozilla.com/D179016

Differential Revision: https://phabricator.services.mozilla.com/D178999

Differential Revision: https://phabricator.services.mozilla.com/D151449

Bug 1492090 - Part 2: Use UTF-8 encoding when printing to stdout and use CompileUtf8Path for xpc-shells. r=nbp

Differential Revision: https://phabricator.services.mozilla.com/D151446

Bug 1492090 - Part 1: Fix some comments, remove a #define, and make one fclose call more robust. r=tcampbell

Differential Revision: https://phabricator.services.mozilla.com/D151445

Bug 1826530 - Implement MessagePumpForNonMainUIThreads for mac. r=xpcom-reviewers,ipc-reviewers,mstange,nika

The MessagePump implemented here is a MessagePumpCFRunLoopBase that also handles
xpcom events.

Differential Revision: https://phabricator.services.mozilla.com/D175101

Bug 1826530 - From the Windows MessagePumpForNonMainUIThreads remove use of NSAutoReleasePool. r=ipc-reviewers,nika

Differential Revision: https://phabricator.services.mozilla.com/D175145

Bug 1826530 - Break platform-dependent MessagePumps out to platform-specific files. r=ipc-reviewers,nika

This makes things a bit clearer when adding the mac implementation.

Differential Revision: https://phabricator.services.mozilla.com/D175100

Backed out 4 changesets (bug 1826530) for causing build bustages in MessagePump_android.cpp CLOSED TREE

Backed out changeset 027080336f71 (bug 1826530)
Backed out changeset 2174d8d45249 (bug 1826530)
Backed out changeset fe9e6fccc2e6 (bug 1826530)
Backed out changeset 2534ba3f140f (bug 1826530)

Bug 1826530 - Implement MessagePumpForNonMainUIThreads for mac. r=xpcom-reviewers,ipc-reviewers,mstange,nika

The MessagePump implemented here is a MessagePumpCFRunLoopBase that also handles
xpcom events.

Differential Revision: https://phabricator.services.mozilla.com/D175101

Bug 1826530 - From the Windows MessagePumpForNonMainUIThreads remove use of NSAutoReleasePool. r=ipc-reviewers,nika

Differential Revision: https://phabricator.services.mozilla.com/D175145

Bug 1826530 - Break platform-dependent MessagePumps out to platform-specific files. r=ipc-reviewers,nika

This makes things a bit clearer when adding the mac implementation.

Differential Revision: https://phabricator.services.mozilla.com/D175100

# ignore-this-changeset

Bug 1821972 part 2: Remove ipc/mscom code only used by the old accessibility architecture based on content process COM proxies. r=bobowen

Nothing else uses any of this or is likely to use it, so I don't think it makes sense to leave it as dead code.

Differential Revision: https://phabricator.services.mozilla.com/D177967

Bug 1821963 part 5: Remove code to prevent handling of window messages while handling PDocAccessible sync IPDL calls. r=handyman

This actually hasn't ever been used in a shipping build of Firefox.
Although sync IPDL was tried with Windos a11y for a while when e10s was still disabled, it was never feasible and was replaced with COM proxying.

Differential Revision: https://phabricator.services.mozilla.com/D177965

This was only ever used by the old accessibility architecture based on content process COM proxies, which is now being removed.

Differential Revision: https://phabricator.services.mozilla.com/D177964

Bug 1821963 part 3: Remove various components supporting the old accessibility architecture based on content process COM proxies. r=nlapre,nalexander

This includes AccessibleHandler, HandlerProvider, IGeckoCustom and the IAccessible2 COM proxy dll.
Even with the new architecture, we still use IAccessible2, but we no longer need a COM proxy because we aren't using COM across processes ourselves.
If clients want to use IAccessible2 across processes, they're responsible for registering a COM proxy themselves as with all other IAccessible2 applications.
Alternatively, they can rely on the IAccessible2 COM proxy which is included with Windows 10 and later.

Differential Revision: https://phabricator.services.mozilla.com/D177963

Bug 1821963 part 2: Remove COM registration supporting the old accessibility architecture based on content process COM proxies. r=nlapre,bobowen

Differential Revision: https://phabricator.services.mozilla.com/D177962

Backed out 9 changesets (bug 1492090) for causing Xpcshell failures at test_async_response_sending.js.

Backed out changeset 7201691d9e37 (bug 1492090)
Backed out changeset a488d7627491 (bug 1492090)
Backed out changeset c4547e2db877 (bug 1492090)
Backed out changeset 1377e06cff9f (bug 1492090)
Backed out changeset a872a1fd5147 (bug 1492090)
Backed out changeset 768f35c0db6b (bug 1492090)
Backed out changeset 65e26a85981e (bug 1492090)
Backed out changeset a42a6210de08 (bug 1492090)
Backed out changeset 87a02a089678 (bug 1492090)

Depends on D178657

Differential Revision: https://phabricator.services.mozilla.com/D178658

Differential Revision: https://phabricator.services.mozilla.com/D178657

Differential Revision: https://phabricator.services.mozilla.com/D151449

Bug 1492090 - Part 2: Use UTF-8 encoding when printing to stdout and use CompileUtf8Path for xpc-shells. r=nbp

Differential Revision: https://phabricator.services.mozilla.com/D151446

Bug 1492090 - Part 1: Fix some comments, remove a #define, and make one fclose call more robust. r=tcampbell

Differential Revision: https://phabricator.services.mozilla.com/D151445

Backed out changeset a92c62e304f0 (bug 1821963)
Backed out changeset da6cba0b0dd4 (bug 1821963)
Backed out changeset 4ed7ca0eb04a (bug 1821963)
Backed out changeset f2fba0ef15d9 (bug 1821963)
Backed out changeset 706e46fc2688 (bug 1821963)
Backed out changeset 6de2b9548dc6 (bug 1821963)