Add _title and _title_callback to all routes.

So, this will override all drupal_set_title calls. I fixed a couple for now...

Note there's #1830588: [META] remove drupal_set_title() and drupal_get_title() for removing drupal_set_title() calls - many of the sub-issues have patches and some are RTBC (I'll try to clean out the RTBC ones next time I'm going through the queue).

@catch it seems very few of those actually address the problems here...

So BreadcrumbTest was still asserting that a menu link title could override a page title from hook_menu. But now that its a route title, it shouldn't be possible.

So, I looked through a lot of the yml files and didn't see any obvious omissions and it's close to RTBC.

One trivial problem I saw was some inconsistency about quoting strings in the YAML files.

e.g.

_title: 'Delete' 

vs.

_title: Settings

while quoting is probably not required in any case, I think it makes for a clearer meaning, so this change quotes titles that were not quoted, and fixes in views_ui.routing.yml one _title with a mismatched quote mark.

Also, in core/modules/node/node.pages.inc the call to drupal_set_title() uses PASS_THROUGH but other calls do not. This needs to be checked - either that's wrong since the title will now be escaped, or other cases are emitting the title unsanitized.

I added Xss::filter() where appropriate in the patch. It passes, and leaves the rest of the drupal_set_titles to their respective issues. I only changed as much as I had to.

RTBC?

Added related

@tim.plunkett - there are a couple shifts directs from drupal_set_title() to using #title in the patch - possibly those should be omitted fro this patch. I agree the ones switching to title callback should be fine.

If you switch them back, tests will fail.

Patch seems fine and yay for killing hook_menu() and a critical both, but...

41 files changed, 205 insertions, 82 deletions.

Was quite surprised about this. I figured it would be more of a 1:1 ratio, but instead it seems we're adding titles *far* more often in routes than we needed to do in the D7 version. Hm. :\

Especially for entities, it seems suboptimal to have to enter those titles by hand. I could see contrib ending up a smörgåsbord of "Create foo" and "Add foo" and "Add new foo" and whatnot. Is this worth discussing in a follow-up?

At any rate, committed and pushed to 8.x to move things along. Thanks!

@webchick - I suspect many of the old hook_menu entries were not removed here, since we will kill them all later.

e.g. aggregator_menu() was still left with a lot of title entries.