This was an issue because guests do not log in with a teamToken, it is implicitly set by MatrixChat when it mounts. The fix is to view_home_page when a login occurs and MatrixChat has this._teamToken set.
- Create a promise that will serve as a lock to be blocked on by things that need to wait for the first sync before accessing state.
- Use this promise to block `view_room` calls until a sync has occured instead of just dropping them silently if the sync hasn't happened yet.
- Store the current room ID in a localStorage item `mx_last_room_id` when `view_room` fires. This persists the last viewed room ID so that it can be restored on refresh, browser quit. This replaces the previous logic which set the room following a sync based on the most recent unread room.
Making sure that a node is intersected by the bottom of the wrapper is a bit overkill, given that we iterate from the bottom. This also prevents the scenario of having no nodes that are not precisely intersected, but possibly straddling the bottom of the wrapper.
Also get rid of the "up" arrow so as not to indiciate direction. This is important because in future the RM will not be based on what has been paginated into the client (but instead RM will be handled server-side) and thus we cannot assert any kind of direction on it relative to the events in the viewport.
The actual fix to https://github.com/vector-im/riot-web/issues/3175 is this change to `_saveScrollState`, which is to pick the trackedScrollToken based on which node is intersected by the bottom of the scroll panel. This is opposed to the previous logic that picked based on which node was the first from the bottom to be above the bottom of the viewport.
In the case where the viewport bottom does not intersect any events, the topmost event is used.
MatrixChat was trying to display an error if the session failed to
restore, but it was never actually being shown because it was just
set as a member variable and therefore never actually caused
a re-render for the error to be displayed. Almost all errors are
caught by _restoreFromLocalStorage which displays the fancy dialog
if your session can't be restored, so I'm not convinced this ever
even tried to do anything anyway. Remove it.
Specifically:
```
JS 2.1.1 (Linux 0.0.0) joining a room over federation should not get stuck at a spinner FAILED
Did not find exactly one match (found: 0) for componentType:function (props, context, updater) {
```
actually meant that the room directory wasn't displayed - probably because the dispatch `view_room_directory` ended up on another tick of the event loop, meaning that the directory wasn't displayedi. The fix attempted in ths commit is to use `this._setPage` instead to view the directory. This uses `setState` to set the screen to the directory, so I'm not entirely convinced this will solve the problem (as `setState` may also end up doing things on another tick.
and
```
JS 2.1.1 (Linux 0.0.0) loading: MatrixClient rehydrated from stored credentials: shows a room view if we followed a room link FAILED
MatrixChat still not ready after 5 tries
awaitRoomView@/home/travis/build/vector-im/riot-web/test/all-tests.js:201363:90
```
was happening probably because in the handler for the `sync` event in `MatrixChat` (around line 840), there was one case in which the `ready` state may not be true (causing all 5 attempts to fail), and this case relied on `starting_room_alias_payload`. This `starting_room_alias_payload` is now redundant because of `initialScreenAfterLogin`, which was added recently.
Only zero the local notification count when we actually send a
read receipt, otherwise we cause a re-render of the RoomList every
time the user moves the cursor in the window, basically.
Use an action and force an update when zeroing the number of notifications in a room. This is better than waiting for a `render` to happen at some point. This will hopefully fix https://github.com/vector-im/riot-web/issues/3257
