The helper functions now return true when a message is on
screen, not when it's off screen, and the names have been
changed accordingly. I also eliminated the at_end parameter,
which was kind of abstract, by having message_is_far_enough_up
and message_is_far_enough_down handle those details.
(imported from commit cdb1543e430f49f23eb1b3a88d9aaff95ce7ca74)
* Move the state into a closure to duplicate it for multiple queues
* Use _.debounce instead of manual setTimeout fiddling
* Have it handle manipulating the message flags
(imported from commit 938f51fd666131a3cec5901d3f3fdd39e203b462)
Functions were supposed to check that messages were unread before
passing them to process_read_messages, but some didn't.
The `mark_messages_as_read` function was essentially that, so
take that name.
(imported from commit 2917fe30d2defb8a047ec32e1bc70d379779276b)
When you read messages in a narrow and then un-narrow, collapse
adjacent messages read in the narrow into a summary row that can
be clicked to expand those messages.
Scoped to staging with feature flags.
The implementation of this within our current MessageList is rather ugly.
(imported from commit bcb3a39d8c0c334136fe86318f18ead03f0f50bf)
