If we check the conditional at registration time, then we can avoid the
conditional at runtime. This commit checks for view path support when
the handler is registered so that runtime calls to `find_dependencies`
won't need to check the conditional. The idea is that
`register_tracker` is called only once where `find_dependencies` may be
called many times.
The thread_safe gem is being deprecated and all its code has been merged
into the concurrent-ruby gem. The new class, Concurrent::Map, is exactly
the same as its predecessor except for fixes to two bugs discovered
during the merge.
The current implementation can't handle some special cases of oddly-formatted Ruby. Now we are able to detect them:
* Multi-line arguments on the `render` call
* Strings containing quotes, e.g. `"something's wrong"`
* Multiple kinds of identifiers - instance variables, class variables and globals
* Method chains as arguments for the `render` call
Also, this fix reduces the rate of "false positives" which showed up when we had calls/access to identifiers containing `render`, like `surrender` and `rendering`.
