All profiles submitted to `JSONOutputCheck` are now checked for valid-looking samples, as in:
- Samples should point into the stackTable.
- stackTable entries should point to the caller in the same stackTable (or null for the root frame).
- stackTable entries should also point into the frameTable.
- frameTable entries should point into the stringTable for the "location".

Differential Revision: https://phabricator.services.mozilla.com/D124738

A scenario for a thread may be that the first entry has an empty sample (usually if stack-sampling is turned off) and no running times (first-ever sample, or "cpu" is off), so it's not output, and there is no corresponding stack table entry.
Then there may be a "same sample" entry.
- If there are no running times, nothing should be output.
- If there are running times, an empty stack should be output, but for that we need to ensure that the root frame is present in the stack table entry, because that represents an empty stack.

Differential Revision: https://phabricator.services.mozilla.com/D124612

Turns out my patch above causes some failures because chrome:// channels
don't have cache information, so we conservatively assume they always
expire, which causes some interesting timing issues in a single test.
Fun stuff.

Tweak the code so that SubresourceCacheValidationInfo has the
pre-existing data:// URI special-case and also special-cases chrome://
URIs.

Differential Revision: https://phabricator.services.mozilla.com/D124921

Differential Revision: https://phabricator.services.mozilla.com/D125007

Bug 1727497 - Add MOZ_DIAGNOSTIC_ASSERT in CacheStreamControlParent::CloseAll(); r=dom-storage-reviewers,jstutte

Differential Revision: https://phabricator.services.mozilla.com/D124454

Bug 1725635 - Tighten when dom/ipc/tests/browser_gc_schedule.js can run r=intermittent-reviewers,jmaher DONTBUILD

Differential Revision: https://phabricator.services.mozilla.com/D124880

This test fails on Thunderbird which doesn't have the telemetry in question.

Differential Revision: https://phabricator.services.mozilla.com/D125014

Helps to understand when something goes wrong.

Differential Revision: https://phabricator.services.mozilla.com/D124899

Differential Revision: https://phabricator.services.mozilla.com/D123825

Differential Revision: https://phabricator.services.mozilla.com/D125025

Differential Revision: https://phabricator.services.mozilla.com/D124308

Now they only operate on WebRenderScrollDataWrapper, rather than
either WebRenderScrollDataWrapper or LayerMetricsWrapper.

Differential Revision: https://phabricator.services.mozilla.com/D124548

Differential Revision: https://phabricator.services.mozilla.com/D124547

Bug 1729117 - Copy relevant comments from LayerMetricsWrapper.h to WebRenderScrollDataWrapper.h. r=hiro

I also took the opportunity to update the main comment describing
the wrapper to refer to ScrollMetadata rather than FrameMetrics.

Differential Revision: https://phabricator.services.mozilla.com/D124546

Differential Revision: https://phabricator.services.mozilla.com/D124545

These APIs were only used by AsyncCompositionManager.

Differential Revision: https://phabricator.services.mozilla.com/D124544

Differential Revision: https://phabricator.services.mozilla.com/D124543

Backed out changeset a3f6c7094ec4 (bug 1728993)
Backed out changeset c8800504488b (bug 1728993)
Backed out changeset c045e3ee9650 (bug 1728993)

Now that WebRender is on in all configurations, this flag only
needs to be set to 'Internal' in 'LayersOnly' gtest fixtures
(which are also renamed in this patch to 'Internal').

Differential Revision: https://phabricator.services.mozilla.com/D124542

Also add a |WebRenderLayerScrollData* root| member for convenience.

Differential Revision: https://phabricator.services.mozilla.com/D124541

Differential Revision: https://phabricator.services.mozilla.com/D124533

Differential Revision: https://phabricator.services.mozilla.com/D124532

Differential Revision: https://phabricator.services.mozilla.com/D124531

Differential Revision: https://phabricator.services.mozilla.com/D124530

Differential Revision: https://phabricator.services.mozilla.com/D124529

Differential Revision: https://phabricator.services.mozilla.com/D124528

Differential Revision: https://phabricator.services.mozilla.com/D124527

Differential Revision: https://phabricator.services.mozilla.com/D124526

Differential Revision: https://phabricator.services.mozilla.com/D124525

Differential Revision: https://phabricator.services.mozilla.com/D124524

Bug 1593381 - Provide a minimal implementation of WebRenderScrollDataWrapper::GetClipRect() which is sufficient to get the tests to pass. r=hiro

Differential Revision: https://phabricator.services.mozilla.com/D124523

Differential Revision: https://phabricator.services.mozilla.com/D124522

Use this ability to set event regions corresponding to the visible region
in TestWRScrollData::Create().

Differential Revision: https://phabricator.services.mozilla.com/D124521

Differential Revision: https://phabricator.services.mozilla.com/D124520

Part of this test had to be removed because it performs an operation,
"change a FrameMetrics which is shared with another Layer", which
the WR data structures do not support, and which does not need
test coverage (since production code cannot do it either).

Differential Revision: https://phabricator.services.mozilla.com/D124297

Differential Revision: https://phabricator.services.mozilla.com/D124296

Bug 1593381 - Port CreateSimpleScrollingLayer(), and the tests that use it, to use WR inputs. r=hiro

Differential Revision: https://phabricator.services.mozilla.com/D124294

For now, the class also retains the ability to use Layer inputs.
This allows porting its subclasses incrementally.

Differential Revision: https://phabricator.services.mozilla.com/D124292

Differential Revision: https://phabricator.services.mozilla.com/D124291