This allows us to update the rich presence description if a channel
is launched from the Wii Menu. It also handles other PPC title
launches, e.g. Smash Bros. Masterpieces.
Host.h: Added Host_TitleChanged().
DolphinNoGUI/MainNoGUI.cpp: Implemented Host_TitleChanged().
DolphinQt/Host.cpp: Implemented Host_TitleChanged().
Android/jni/MainAndroid.cpp: Stubbed Host_TitleChanged().
DSPTool/StubHost.cpp: Stubbed Host_TitleChanged().
UnitTests/StubHost.cpp: Stubbed Host_TitleChanged().
Given this is actually a part of the Host interface, this should be
placed with it.
While we're at it, turn it into an enum class so that we don't dump its
contained values into the surrounding scope. We can also make
Host_Message take the enum type itself directly instead of taking a
general int value.
After this, it'll be trivial to divide out the rest of Common.h and
remove the header from the repository entirely
