Commit graph

385 commits

Author SHA1 Message Date
Emilio Cobos Álvarez
2a1828662f Bug 1696507 - Remove support for NO_UNLINK version of cycle collector macros. r=smaug
And fix existing users of course.

The frame loader one is the only one slightly scary (but if it causes
trouble we could make nsObjectLoadingContent::Unlink a no-op).

Differential Revision: https://phabricator.services.mozilla.com/D107269
2021-03-10 19:50:40 +00:00
Gerald Squelart
2416d881e2 Bug 1691589 - Reduce reliance on GeckoProfiler.h when only labels (and maybe markers) are needed - r=necko-reviewers,geckoview-reviewers,sg,agi,florian
There are no code changes, only #include changes.
It was a fairly mechanical process: Search for all "AUTO_PROFILER_LABEL", and in each file, if only labels are used, convert "GeckoProfiler.h" into "ProfilerLabels.h" (or just add that last one where needed).
In some files, there were also some marker calls but no other profiler-related calls, in these cases "GeckoProfiler.h" was replaced with both "ProfilerLabels.h" and "ProfilerMarkers.h", which still helps in reducing the use of the all-encompassing "GeckoProfiler.h".

Differential Revision: https://phabricator.services.mozilla.com/D104588
2021-02-16 04:44:19 +00:00
Mats Palmgren
b80f010fb4 Bug 1687239 part 3 - Remove the PluginProblem UA Widget and related CSS pseudos. r=emilio
Differential Revision: https://phabricator.services.mozilla.com/D102901
2021-01-25 11:53:57 +00:00
Mats Palmgren
b41a2b9d21 Bug 1687239 part 2 - Remove plugin support from layout/. r=emilio
Note that there's still a little plugin related code in
widget/ and gfx/ etc after this.  That can be removed
once we remove plugin support from dom/ etc.
The removal from layout/ should be pretty complete though.

Differential Revision: https://phabricator.services.mozilla.com/D102140
2021-01-25 11:53:49 +00:00
Emilio Cobos Álvarez
925ab25267 Bug 1684220 - Remove some dead plugins code. r=smaug
Differential Revision: https://phabricator.services.mozilla.com/D100472
2021-01-04 20:12:05 +00:00
Masayuki Nakano
968d02a1a9 Bug 1683226 - part 12: Get rid of nsIWidget::SetPluginFocus() r=m_kato
Differential Revision: https://phabricator.services.mozilla.com/D100386
2020-12-24 02:46:02 +00:00
Masayuki Nakano
d876b20aaa Bug 1683226 - part 2: Make HTMLEmbedElement and HTMLObjectElement stop overriding nsIContent::GetDesiredIMEState() r=smaug
Currently, they are never focusable when its type is "plugin".
So, making stop them returning `IMEEnabled::Plugin` won't change
anything, but it guarantees that nobody will see `IMEEnabled::Plugin`
at runtime.  This is a preparation for the following patches.

Differential Revision: https://phabricator.services.mozilla.com/D100101
2020-12-21 05:52:26 +00:00
Masayuki Nakano
d27602eee6 Bug 1683226 - part 1: Make IMEState::Enabled an enum class r=m_kato,geckoview-reviewers
Before deleting `IMEState::Enabled::PLUGIN`, let's make it an enum class
for making the change safer.  Almost all of this change is done by
"replace" of VSCode.

Differential Revision: https://phabricator.services.mozilla.com/D100100
2020-12-21 05:52:03 +00:00
Masatoshi Kimura
3424a95ee0 Bug 1682103 - Make nsContentPolicyType a CEnum type. r=ckerschb
Differential Revision: https://phabricator.services.mozilla.com/D99580
2020-12-16 11:36:47 +00:00
Cameron McCormack
5e3e854648 Bug 1668106 - Store subdocument intrinsic size and ratio on content rather than frame. r=dholbert
This avoids a problem where we receive the IPC message from the child
with updated intrinsics before an <embed> or <object> has had its frame
constructed in the parent, and drop the update.

Differential Revision: https://phabricator.services.mozilla.com/D99304
2020-12-10 21:34:38 +00:00
Simon Giesecke
971b645fe3 Bug 1660470 - Add missing include directives/forward declarations. r=nika
Differential Revision: https://phabricator.services.mozilla.com/D87865
2020-11-23 16:21:38 +00:00
David Parks
3ad73d34d7 Bug 1675349: Forbid elements representing blocked plugins from accepting focus r=jmathies
As part of the fallback for unsupported plugin elements, we deny them focus.  Since elements can be programmatically changed, and object/embed elements can change internal "type" by updating their data/src attributes, and because that type is decided asynchronously, we may need to give up focus if our element has it.

Differential Revision: https://phabricator.services.mozilla.com/D95903
2020-11-18 15:55:52 +00:00
David Parks
1e71ef1cb8 Bug 1675349: Replace plugin behavior with a basic fallback r=jmathies,mixedpuppy
The browser currently only enables plugin behavior for Flash and our internal test plugins.  This patch replaces support for those plugins with a simple fallback that shows a transparent region where the plugin would have been.  It removes the file system search(es) for the plugin dynamic libraries and short-circuits the logic to determine if plugins should do something special -- all implementations now behave the same in the presence of plugin elements.

The new behavior is:
1. If the <object> or <embed> element lists a type of something other than "x-shockwave-flash" or "x-test" then the behavior is unchanged.  This means that non-plugin types behave properly and unknown types (for example, typos) are also unaffected (they reduce to 0x0 elements).
2. If the <object> element has an HTML fallback in the DOM (see spec for <object> elements) then the fallback is always shown.
3. Otherwise, the element is shown as a transparent region with the size specified in attributes.

Differential Revision: https://phabricator.services.mozilla.com/D95902
2020-11-18 15:55:34 +00:00
Bogdan Tara
56346a0425 Backed out 19 changesets (bug 1675349) for lint failures on browser_ext_browsingData_pluginData and test_archive CLOSED TREE
Backed out changeset 244e0f2b410c (bug 1675349)
Backed out changeset ba5724069dd4 (bug 1675349)
Backed out changeset 37fca259c7e9 (bug 1675349)
Backed out changeset f2b16caca1fc (bug 1675349)
Backed out changeset 28835d4935be (bug 1675349)
Backed out changeset eb913f58953a (bug 1675349)
Backed out changeset 19e3cb80f469 (bug 1675349)
Backed out changeset d9723f3a3a7e (bug 1675349)
Backed out changeset c888dfcdf70e (bug 1675349)
Backed out changeset 48f153341af6 (bug 1675349)
Backed out changeset 7fc67a9b2932 (bug 1675349)
Backed out changeset 1cee4d97f801 (bug 1675349)
Backed out changeset 59a0cb79c7c1 (bug 1675349)
Backed out changeset 43d349fa37b1 (bug 1675349)
Backed out changeset c84bfb6eae59 (bug 1675349)
Backed out changeset 38e9af69ae57 (bug 1675349)
Backed out changeset 3255c1ab3059 (bug 1675349)
Backed out changeset 2f3eaf9c342c (bug 1675349)
Backed out changeset 769e5c0db4c2 (bug 1675349)
2020-11-18 06:06:36 +02:00
David Parks
3c0d56e32c Bug 1675349: Forbid elements representing blocked plugins from accepting focus r=jmathies
As part of the fallback for unsupported plugin elements, we deny them focus.  Since elements can be programmatically changed, and object/embed elements can change internal "type" by updating their data/src attributes, and because that type is decided asynchronously, we may need to give up focus if our element has it.

Differential Revision: https://phabricator.services.mozilla.com/D95903
2020-11-18 03:04:02 +00:00
David Parks
ca8ad84d31 Bug 1675349: Replace plugin behavior with a basic fallback r=jmathies,mixedpuppy
The browser currently only enables plugin behavior for Flash and our internal test plugins.  This patch replaces support for those plugins with a simple fallback that shows a transparent region where the plugin would have been.  It removes the file system search(es) for the plugin dynamic libraries and short-circuits the logic to determine if plugins should do something special -- all implementations now behave the same in the presence of plugin elements.

The new behavior is:
1. If the <object> or <embed> element lists a type of something other than "x-shockwave-flash" or "x-test" then the behavior is unchanged.  This means that non-plugin types behave properly and unknown types (for example, typos) are also unaffected (they reduce to 0x0 elements).
2. If the <object> element has an HTML fallback in the DOM (see spec for <object> elements) then the fallback is always shown.
3. Otherwise, the element is shown as a transparent region with the size specified in attributes.

Differential Revision: https://phabricator.services.mozilla.com/D95902
2020-11-18 03:08:29 +00:00
Christoph Kerschbaumer
faf05f7d19 Bug 1552168: Remove pref security.data_uri.unique_opaque_origin. r=smaug
Differential Revision: https://phabricator.services.mozilla.com/D92087
2020-10-08 16:55:25 +00:00
Cameron McCormack
a9b6211496 Bug 1658343 - Propagate intrinsic sizes from SVG documents in embed/object to parent using IPC. r=kmag,dholbert
Differential Revision: https://phabricator.services.mozilla.com/D90055
2020-09-21 02:09:57 +00:00
Emilio Cobos Álvarez
948fa5c6d2 Bug 1664156 - Remove -moz-suppressed. r=edgar
Per spec we shouldn't behave differently depending on how we blocked the
image/object/etc.

This may have made sense in the past when ad blockers were implemented
via nsIContentPolicy, but I think nowadays it doesn't make sense, and
showing fallback is preferred.

There's a couple extra cleanups we can do after this lands, like
removing HTMLImageElement.imageBlockingStatus and simplifying a bit that
code. But I'll do that in a separate bug.

Differential Revision: https://phabricator.services.mozilla.com/D89912
2020-09-13 11:33:13 +00:00
Noemi Erli
733e3b440c Backed out changeset 64eb902728bc (bug 1664156) for causing mochitest failures in test_meta_csp_self.html CLOSED TREE 2020-09-12 22:56:18 +03:00
Emilio Cobos Álvarez
4b18c556e4 Bug 1664156 - Remove -moz-suppressed. r=edgar
Per spec we shouldn't behave differently depending on how we blocked the
image/object/etc.

This may have made sense in the past when ad blockers were implemented
via nsIContentPolicy, but I think nowadays it doesn't make sense, and
showing fallback is preferred.

There's a couple extra cleanups we can do after this lands, like
removing HTMLImageElement.imageBlockingStatus and simplifying a bit that
code. But I'll do that in a separate bug.

Differential Revision: https://phabricator.services.mozilla.com/D89912
2020-09-12 17:39:18 +00:00
Emilio Cobos Álvarez
1ef2a5628a Bug 1664432 - Remove -moz-user-disabled. r=edgar
We treat it exactly the same as -moz-broken. The pseudo-class is not
exposed to content, so I don't think we have a reason to keep it around.

Differential Revision: https://phabricator.services.mozilla.com/D89904
2020-09-11 19:26:40 +00:00
Jeff Walden
6d5beafab1 Bug 1663365 - Move various Object-related functions to a new js/public/Object.h header. r=jandem
Differential Revision: https://phabricator.services.mozilla.com/D89333
2020-09-08 22:55:38 +00:00
Anny Gakhokidze
8b553ecfcf Bug 1589102 - Part 1: Enable about:srcdoc loads via DocumentChannel, r=mattwoodrow
This patch enables sandboxed srcdoc loads to take place via DocumentChannel,
and adds mechanisms for enabling unsandboxed ones.

Both unsandboxed srcdoc, and in subsequent patches, about:blank, loads require
that the triggering principal and the principal to inherit point to the same
instance if the load takes place in the same process as where we are inheriting
those principals from. We save those principals on a target browsing context before
we load the URI, and later, when we are deserializing LoadInfoArgs into
LoadInfo in the content process, we retrieve the saved principals if the
current load identifier of the target BC matches the load identifier saved
along with the principals.

We also need to make sure that during a process switch for about:srcdoc load,
we don't use the original URI for about:srcdoc to determine the remote type and
instead we use channel's result principal.

Differential Revision: https://phabricator.services.mozilla.com/D85079
2020-08-28 17:20:30 +00:00
Nika Layzell
482d731e3a Bug 1614524 - Part 1: Add support for process-switching object/embed loads, r=mattwoodrow,smaug,kamidphish
By passing a weak reference back to the DocumentChannelParent into
DocumentLoadListener for object loads, we are able to handle process switching
loads by asking the content process to create a BrowsingContext, and delaying
the real process switch until it becomes available.

The load then completes as it would before, acting as a normal process-switching
subframe load.

Differential Revision: https://phabricator.services.mozilla.com/D86580
2020-08-18 16:49:34 +00:00
Butkovits Atila
3bd0e5497c Backed out 10 changesets (bug 1589102) for failure at browser_saveHeapSnapshot_e10s_01.js CLOSED TREE
Backed out changeset 0d22ad297b19 (bug 1589102)
Backed out changeset 14bcaf2a452c (bug 1589102)
Backed out changeset 20905f91e2bb (bug 1589102)
Backed out changeset 29ee0fbe855f (bug 1589102)
Backed out changeset d1f6185030af (bug 1589102)
Backed out changeset 31949872cc1d (bug 1589102)
Backed out changeset ec04e1a20597 (bug 1589102)
Backed out changeset ffe8da473b91 (bug 1589102)
Backed out changeset 3b92f7306c64 (bug 1589102)
Backed out changeset b187548e258f (bug 1589102)
2020-08-05 21:47:50 +03:00
Anny Gakhokidze
e903c66d34 Bug 1589102 - Part 1: Enable about:srcdoc loads via DocumentChannel, r=mattwoodrow
This patch enables sandboxed srcdoc loads to take place via DocumentChannel,
and adds mechanisms for enabling unsandboxed ones.

Both unsandboxed srcdoc, and in subsequent patches, about:blank, loads require
that the triggering principal and the principal to inherit point to the same
instance if the load takes place in the same process as where we are inheriting
those principals from. We save those principals on a target browsing context before
we load the URI, and later, when we are deserializing LoadInfoArgs into
LoadInfo in the content process, we retrieve the saved principals if the
current load identifier of the target BC matches the load identifier saved
along with the principals.

We also need to make sure that during a process switch for about:srcdoc load,
we don't use the original URI for about:srcdoc to determine the remote type and
instead we use channel's result principal.

Differential Revision: https://phabricator.services.mozilla.com/D85079
2020-08-05 16:44:01 +00:00
Emilio Cobos Álvarez
05bbb6ac23 Bug 1652618 - Ensure UA widgets are attached and detached synchronously. r=smaug
This changes the UA widget setup (again). What is going on in this
test-case is that we have a marquee inside a video, two things that have
their own UA widget. Given how the code is currently written, the
runnable to attach and set up the marquee's widget is posted before than
the video one (which is potentially reasonable).

However that means that the marquee one runs before and flushes layout,
and catches the video in an inconsistent state (in the composed doc, but
without a shadow root). That in turn messes up reflow because
nsVideoFrame assumes stuff.

Rather than putting the attach / detach logic in script runners, just
run that bit synchronously, and post only the event async. I audited the
consumers of those events and it seems fine to me, they either already
deal with the possibility of the shadow root being already detached or
they don't care.

For teardown, none of the destructors of the UA widgets rely on the
shadow root being still attached to the element.

Differential Revision: https://phabricator.services.mozilla.com/D84487
2020-07-24 15:43:20 +00:00
Narcis Beleuzu
ce05a24710 Backed out changeset 8323b7bb5e1a (bug 1652618) for mochitest failures on test_audiocontrols_dimensions.html . CLOSED TREE 2020-07-23 00:49:31 +03:00
Emilio Cobos Álvarez
5f53233ca1 Bug 1648064 - Switch DOM images to work like CSS images for the purposes of printing. r=tnikkel,smaug
Make them perform the image load (if needed), instead of copying the
image requests from the original document.

This is needed for CSS for stuff like:

@media print {
  #foo::before {
    content: url(bar.png);
  }
}

And so on. For images, we should do this as well. Nothing prevents you
from doing:

  <picture>
    <source srcset="print.png" media="print">
    <source srcset="screen.png" media="not print">
    <img>
  </picture>

And that should in theory work. It works after this patch, and I added a
test for that.

This patch is a bit bigger than I'd like, but I didn't find a more
reasonable way to split it up.

Making static docs able to do image loads is most of the patch and is
mostly straight-forward. This allows to remove the hacky "change the
loading document" thing that CSS images do, which is just working around
the CSP of the print document.

I need to enable background colors in printpreview_helper so as to be
able to have a reference page for all the different image types.

Differential Revision: https://phabricator.services.mozilla.com/D81779
2020-07-22 20:29:00 +00:00
Emilio Cobos Álvarez
312039fb70 Bug 1652618 - Ensure UA widgets are attached and detached synchronously. r=smaug
This changes the UA widget setup (again). What is going on in this
test-case is that we have a marquee inside a video, two things that have
their own UA widget. Given how the code is currently written, the
runnable to attach and set up the marquee's widget is posted before than
the video one (which is potentially reasonable).

However that means that the marquee one runs before and flushes layout,
and catches the video in an inconsistent state (in the composed doc, but
without a shadow root). That in turn messes up reflow because
nsVideoFrame assumes stuff.

Rather than putting the attach / detach logic in script runners, just
run that bit synchronously, and post only the event async. I audited the
consumers of those events and it seems fine to me, they either already
deal with the possibility of the shadow root being already detached or
they don't care.

For teardown, none of the destructors of the UA widgets rely on the
shadow root being still attached to the element.

Differential Revision: https://phabricator.services.mozilla.com/D84487
2020-07-22 19:42:37 +00:00
Narcis Beleuzu
46367e2f7d Backed out 6 changesets (bug 1648064) for wp failures on test_printpreview.xhtml . CLOSED TREE
Backed out changeset 8ac892c60eda (bug 1648064)
Backed out changeset 189401f7b6e8 (bug 1648064)
Backed out changeset 2598e2706bd0 (bug 1648064)
Backed out changeset 4ec12eb9788c (bug 1648064)
Backed out changeset f735d4f6b21f (bug 1648064)
Backed out changeset 0fed6928b53d (bug 1648064)
2020-07-22 21:28:10 +03:00
Emilio Cobos Álvarez
08db8b4b15 Bug 1648064 - Switch DOM images to work like CSS images for the purposes of printing. r=tnikkel,smaug
Make them perform the image load (if needed), instead of copying the
image requests from the original document.

This is needed for CSS for stuff like:

@media print {
  #foo::before {
    content: url(bar.png);
  }
}

And so on. For images, we should do this as well. Nothing prevents you
from doing:

  <picture>
    <source srcset="print.png" media="print">
    <source srcset="screen.png" media="not print">
    <img>
  </picture>

And that should in theory work. It works after this patch, and I added a
test for that.

This patch is a bit bigger than I'd like, but I didn't find a more
reasonable way to split it up.

Making static docs able to do image loads is most of the patch and is
mostly straight-forward. This allows to remove the hacky "change the
loading document" thing that CSS images do, which is just working around
the CSP of the print document.

I need to enable background colors in printpreview_helper so as to be
able to have a reference page for all the different image types.

Differential Revision: https://phabricator.services.mozilla.com/D81779
2020-07-22 14:39:43 +00:00
Edgar Chen
2003a00dfc Bug 1608501 - Part 3: Clean up image request in DestroyContent; r=smaug
Differential Revision: https://phabricator.services.mozilla.com/D82875
2020-07-21 12:08:14 +00:00
Edgar Chen
797c3c86a1 Bug 1608501 - Part 2: Rename nsObjectLoadingContent::DestroyContent to ::Destroy; r=smaug
Depends on D82729

Differential Revision: https://phabricator.services.mozilla.com/D84341
2020-07-21 16:11:29 +00:00
Edgar Chen
e10324adb1 Bug 1608501 - Part 1: Rename nsImageLoadingContent::DestroyImageLoadingContent to ::Destroy; r=smaug
Differential Revision: https://phabricator.services.mozilla.com/D82729
2020-07-21 12:08:14 +00:00
Dan Glastonbury
081870285c Bug 1646899 - P4: Handle object & embed via DocumentChannel. r=mattwoodrow,jya
Pass internal content policy type to DLL and switch behavior depending on type
being loaded. This implementation immediately redirects channel back to the
content process for further handling.



Depends on D80406

Differential Revision: https://phabricator.services.mozilla.com/D80407
2020-07-21 01:01:05 +00:00
Frederik Braun
a7153982e8 Bug 1366973: Rename security flags to not contain DATA anymore r=geckoview-reviewers,ckerschb,snorp
Differential Revision: https://phabricator.services.mozilla.com/D83490
2020-07-15 11:20:45 +00:00
Narcis Beleuzu
8981494089 Backed out 5 changesets (bug 1646899) for mochitest failures on DocumentLoadListener.cpp . CLOSED TREE
Backed out changeset f41ac122a801 (bug 1646899)
Backed out changeset 86a5e0827050 (bug 1646899)
Backed out changeset d2fd0f955e24 (bug 1646899)
Backed out changeset 7a7194146fe1 (bug 1646899)
Backed out changeset 4731d76dae88 (bug 1646899)
2020-07-13 05:43:30 +03:00
Dan Glastonbury
f5fd7b3d97 Bug 1646899 - P4: Handle object & embed via DocumentChannel. r=mattwoodrow,jya
Pass internal content policy type to DLL and switch behavior depending on type
being loaded. This implementation immediately redirects channel back to the
content process for further handling.

Differential Revision: https://phabricator.services.mozilla.com/D80407
2020-07-13 00:48:57 +00:00
Simon Giesecke
9364b353d4 Bug 1648010 - Remove NS_NAMED_LITERAL_CSTRING and NS_NAMED_LITERAL_STRING macros. r=froydnj
Differential Revision: https://phabricator.services.mozilla.com/D80631
2020-07-01 08:42:31 +00:00
Simon Giesecke
cd8b8939b9 Bug 1648010 - Replace uses of NS_LITERAL_STRING/NS_LITERAL_CSTRING macros by _ns literals. r=geckoview-reviewers,jgilbert,agi,hsivonen,froydnj
Differential Revision: https://phabricator.services.mozilla.com/D80860
2020-07-01 08:29:29 +00:00
Kashav Madan
960bd54cfd Bug 1646563 - Remove BrowserId from nsFrameLoaderOwner, r=nika
We can just use BrowsingContext::BrowserId directly, so it's unnecessary to have
the field on nsFrameLoaderOwner as well.

This also makes it so that we only ever generate browser IDs in
BrowsingContext::CreatedDetached.

Differential Revision: https://phabricator.services.mozilla.com/D80121
2020-06-22 21:46:03 +00:00
Kashav Madan
1a71fed80e Bug 1580766 - Add a unique ID for the BrowsingContext tree inside a browser element. r=kmag
This adds a `browserId` property to all browsing contexts. This ID is the same
for the entire tree of contexts inside a frame element. Each new top-level
context created for a given frame also inherits this ID. This allows identifying
the frame element for a given browsing context.

Originally authored by :mossop in D56245.

Differential Revision: https://phabricator.services.mozilla.com/D77911
2020-06-16 18:12:46 +00:00
Razvan Maries
73dfe9d277 Backed out changeset 585e0230b2d5 (bug 1580766) as requested. CLOSED TREE 2020-06-16 21:01:26 +03:00
Dave Townsend
7a5ade2788 Bug 1580766 - Add a unique ID for the BrowsingContext tree inside a browser element. r=kmag
This adds a `browserId` property to all browsing contexts. This ID is the same
for the entire tree of contexts inside a frame element. Each new top-level
context created for a given frame also inherits this ID. This allows identifying
the frame element for a given browsing context.

Originally authored by :mossop in D56245.

Differential Revision: https://phabricator.services.mozilla.com/D77911
2020-06-16 17:25:16 +00:00
Simon Giesecke
f458cd246a Bug 1626570 - Improve handling of copying arrays in dom/base/. r=emilio
Differential Revision: https://phabricator.services.mozilla.com/D73625
2020-05-05 10:08:02 +00:00
Emilio Cobos Álvarez
761e9dfe4c Bug 1635094 - Cleanup the ReferrerInfo code. r=ckerschb
The cast in InitWithNode is wrong. AsElement() asserts instead of
checking the flag, so we always pass an element (and if we didn't we'd
have type confusion problems). I audited the callers and we're fine.

Anyhow, always require an element, and add two convenience constructors
for C++ code.

Differential Revision: https://phabricator.services.mozilla.com/D73636
2020-05-04 18:50:20 +00:00
Cosmin Sabou
71a40eae48 Backed out 2 changesets (bug 1635094) for build bustages on nsMacShellService.cpp. CLOSED TREE
Backed out changeset 0a2b0c6ea19a (bug 1635094)
Backed out changeset ead4f26f76ee (bug 1635094)
2020-05-04 20:04:06 +03:00
Emilio Cobos Álvarez
6dde680742 Bug 1635094 - Cleanup the ReferrerInfo code. r=ckerschb
The cast in InitWithNode is wrong. AsElement() asserts instead of
checking the flag, so we always pass an element (and if we didn't we'd
have type confusion problems). I audited the callers and we're fine.

Anyhow, always require an element, and add two convenience constructors
for C++ code.

Differential Revision: https://phabricator.services.mozilla.com/D73636
2020-05-04 16:26:51 +00:00