With this change, on my browser, reloading a page in development after
changing a CSS file is about 25% faster than simply splitting the CSS
code between `application.css` and `vendored.css`. Compared to using
only one `application.css` file containing everything, reloading a page
in development is about 35% faster.
The combined size of all the generated stylesheets is now about 0.5%
bigger. Not sure why (maybe placeholder selectors?), but the difference
is negligible.
Note that we could load the `administration.css` file only in the admin
area, reducing the size of the page for people accessing the public
area. However, the size of this stylesheet (compressed) is 28K, which is
less than 3% of the overall size of a page and, on the other hand,
there's a risk of some styles no longer being applied because we might
have overlooked the fact that some styles in the `administration.css`
are also applied to the public area.
So, for now, we're still loading the administration styles in the public
area. We might reconsider in the future.
In commit 905ac48bb we mentioned:
> Since we don't use `asset_path` to reference assets in the public
> folder, we can safely disable the `unknown_asset_fallback` option.
However, `asset_path` is used by the wicked_pdf gem when calling the
`wicked_pdf_stylesheet_link_tag` method. This method also checks the CSS
files, searching for `url()` calls and converting any relative URLs
referenced there to absolute URLs.
However, when compiling assets on production, our `application.css` file
contains the following line imported from Leaflet which says:
```
behavior: url(#default#VML);
```
When passing this URL to `asset_path` (which is something the wicked_pdf
gem does automatically), it doesn't find the URL, and so this call
crashes unless we enable then `unknown_asset_fallback` option.
Since the dashboard poster is a feature we might remove in the future,
we're avoiding changing a Rails global configuration just for this
feature. So, instead of enabling the `unknown_asset_fallback` option,
we're changing the `poster.pdf` view so it doesn't load all the CSS of
the application but only the CSS it needs.
Note we aren't adding a test case because this bug is only present on
production environments when assets have been precompiled.
