DO NOT LAND - This handles the build system bits. What is still
needed is to update the consumers of the .h files (all the #include
lines) to use the fine-grained imports.

I did some of the build bits for this ticket, but I don't have a good way to determine what new includes are needed and I don't want to spend the time to work them out by hand. etoop, can you find an assignee for that? The pay off is that adding @WrapForJNI should recompile fewer files, which I expect will produce faster builds as GV devs evolve the JNI wrapper signatures.

adding geckoview whiteboard tag to send this to triage.

P3 nice to have for internal GV developer ergonomics

This handles the build system bits.

The subsequent patch will restore the "unified"
GeneratedJNI{Natives,Wrappers}.h header files, and will be folded into
this one before landing.

What will still remain is to update the consumers of the .h files (all
the current #include lines) to use the fine-grained imports. At that
time the "unified" header files can be removed entirely.

It's not trivial to split the existing "unified" include declaration
into granular include declarations, so we continue generating a
unified header that can be incrementally abandoned until it can be
jettisoned.

Depends on D58572

This establishes a "high-water" mark that will make new files not be
"unified", and will allow to burn down the list of files require
unification.

Depends on D58573

Depends on D58574

I needed something to ease back into actual work, so I took a second look at this. Try build is percolating at https://treeherder.mozilla.org/#/jobs?repo=try&revision=1da8a6bb0cf2eb4d748aad9bce83b463c6a3221d.

There are some r+ patches which didn't land and no activity in this bug for 2 weeks.
:nalexander, could you have a look please?
For more information, please visit auto_nag documentation.

(In reply to Release mgmt bot [:sylvestre / :calixte / :marco for bugbug] from comment #13)

There are some r+ patches which didn't land and no activity in this bug for 2 weeks.
:nalexander, could you have a look please?
For more information, please visit auto_nag documentation.

Sure! I'm passing this work over to :aklotz (who I have assigned). This is ready to go, modulo that :snorp asked for a more reasonable file name scheme. I think that will be on Aaron (or on follow-up).

We update the name generation code to dump the files into:

OBJDIR/widget/android/jni/GeneratedJNI{Natives, Wrappers}

which are then exported to mozilla/jni/natives and mozilla/jni/wrappers

Depends on D58574

I added part 1d to fix the naming scheme. I'll file follow-up bugs for transitioning remaining includes, as well as perhaps autogenerating dependencies (which I have discussed the possibility of with Nathan, and we can experiment with).

Backed out for build bustages at SocketProcessParent.cpp.

Push with failure: https://treeherder.mozilla.org/#/jobs?repo=autoland&selectedTaskRun=HJqz0_u1Rg-3OA46-bgpkQ-0&resultStatus=success%2Ctestfailed%2Cbusted%2Cexception&searchStr=b&revision=192294c1413a95391a330f1390967894c547d914

Failure log: https://treeherder.mozilla.org/logviewer.html#/jobs?job_id=302007026&repo=autoland&lineNumber=18701

Backout: https://hg.mozilla.org/integration/autoland/rev/5e05ebce1da8b57a31df92ce710186413335642b

grr, probably some dirs that need updating since this patchset was first written...

Depends on D58575

https://hg.mozilla.org/mozilla-central/rev/298f90202eda
https://hg.mozilla.org/mozilla-central/rev/9464ad22d412
https://hg.mozilla.org/mozilla-central/rev/bf98f3293602
https://hg.mozilla.org/mozilla-central/rev/6f2d5ac0672d
https://hg.mozilla.org/mozilla-central/rev/ba407e8fac92
https://hg.mozilla.org/mozilla-central/rev/6a8277223f6d