* Eliminate unnecessary temporary in VTableStack::move, which also fixes calling the destructor on the incorrect instance
* Make move consistent: it destructs the src, not the dest, which is always empty
* delete doesn't need a null guard
* Conversions to void* don't need a cast
* Tile timing
* Refactor logging code
* Keep the scope of `messageStream` constrained
* Make log message more clear
* Fix crash issue if onlineResponse.data is null
Render threads won't have a scheduler, so we create one that is
shared by all the maps rendering at this thread. The bad side
effect of this is that we need to wake up the render thread
to process events.
Mapbox GL should get rid of processing events on the render
thread. This solution is a workaround.
Before this change, we've tried to open the database in read/write, but not create mode. In situations where the database didn't exist yet, this logged an error to the console, and we proceeded to opening it again in read/write/create mode, which actually created the file. The reason we did this is so that we could detect really old caching databases from January 2016 in case a developer upgraded from an older SDK (iOS v3.1 and earlier, Android v3.2 and earlier) that didn't have https://github.com/mapbox/mapbox-gl-native/pull/3715 yet.
However, these error messages, while innocent, look scary in the console and some users suspect that it's a bug. This change opens the file directly in read/write/create mode, omitting the first failed attempt. To handle old cache databases, we're now deleting the `http_cache` table, which was the only table in those old databases, and create the new schema, rather than deleting the entire file and recreating the Database object. In most scenarios, this will lead to one fewer opening attempt, while the database migration will continue to work for the few users who upgrade all the way from a January 2016 SDK.
Additionally, this fixes a mismatch between the Qt and non-Qt implementation: Qt doesn't support opening a file in read/write mode without the create flag. This means that we've seen a different control flow on Qt compared to the non-Qt implementation when opening a database.
