Append text chunks to either the start or end of the text fragment,
depending on the text direction. The direction is determined by what
script its code points are from.
Always assuming unpremultiplied color data only worked for PNGs (which
are specced as unpremultiplied) and bitmaps with alpha set to 100%.
Properly propagate the Gfx::AlphaType of a bitmap to Skia.
The reference tests were updated to reflect this change, but visually
it's practically impossible to see the difference. A new test was added
to clearly expose this issue.
Fixes#1104
These test work with LibGfx painter but won't longer work after
switching to Skia, because it produces slightly different antialiasing,
rounding in color blending, etc.
This change will make it easier to disable screenshot comparison tests
on a specific platform or have per-platform expectations.
Additionally, it's nice to be able to tell if a ref-test uses a
screenshot as an expectation by looking at the test path.
