Fix scroll up, down pagination test
NB: this test may not fail on Travis, although it did fail locally without a fix: #563.
Once the test has scrolled the panel to the top, to the earliest events, it should be able to forward paginate, because some degree of unpagination occurs. This does assume that unpagination will occur when scrolling to the beginning of the events and that unpagination should allow pagination again in the same direction.
Instead of checking that the first event is no longer the first event (varies due to unpagination), check instead that the most recent event can be seen when scrolling all the way down to the bottom of the TimelinePanel.
Scrolling past the bottom of content seems to have strange behaviour, which isn't a useful part of the test. So now the test will scroll down until the last event instead.
Fix pagination issue where recent events are lost
Scrolling up a few pages followed by scrolling down to the most recent events previously caused some events to go missing. A test has been modified in conjunction with this fix to make sure that this failure mode is tested for in future. This commit should fix the issue, and the most recent events should be paginated back in.
Also, the net change of nil is detected as having the first and last events being _different_. The summary should only include those that have their first and last events being the _same_ because that is a net change (within the block of member events).
* Fix join/part collapsing regressions
* Simplify loop
* Explain e,e
* Explain return null in _renderSummary
* Kill it properly
* Move . to _renderSummary
* Only use the first and last events to decide whether a net change has occured
* Do not sort events by TS before summarising
* fix loop and comment
* remove data-number-events
* Better explanation comment in _renderSummary
* Less tortuous comment
Instead of using a window of a fixed number of events, unpaginate based on the distance of the viewport from the end of the scroll range.
The ScrollPanel uses the scrollTokens to convey to its parent (the TimelinePanel, in this case) the point to unpaginate up to. The TimelinePanel then takes a chunk of events off the front or back of `this.state.events` using `timelineWindow.unpaginate`.
Fixes https://github.com/vector-im/vector-web/issues/2020
* Use a list of callbacks for things that need tinting.
Rather than gutwrenching the internals of TintableSVG inside the Tinter.
* Share a data: url for the tinted download svg in MFileBody
* Check image exists before tinting
* Add comments
* Use fetch+DomParser rather than XMLHttpRequest
* Remove comment about XMLHttpRequest
* Send a thumbnail when sending a m.image
* Use the 'thumbnail_file' when displaying encrypted images
* Whitespace
* Generate thumbnails for m.video
* Fix docstring, remove unused vars, use const
* Don't change the upload promise behaviour
* Polyfill for Canvas.toBlob to support older browsers
* Lowercase for integer types in jsdoc
