This functionality stopped being relevant after the removal of Flash support
in January 2021. The last remaining PPAPI plugin (PDF viewer) will switch to
a non-plugin implementation (PdfUnseasoned) in M100.
- CefURLRequest::Create is no longer supported in the renderer process
(see https://crbug.com/891872). Use CefFrame::CreateURLRequest instead.
- Mac platform definitions have been changed from `MACOSX` to `MAC`
(see https://crbug.com/1105907) and related CMake macro names have
been updated. The old `OS_MACOSX` define is still set in code and CMake
for backwards compatibility.
- Linux ARM build is currently broken (see https://crbug.com/1123214).