Under ARC (Automatic Reference Counting), assigning to an Objective-C
pointer has different semantics than assigning to a void* pointer.
This makes it dangerous to treat the same memory address as an
Objective-C pointer in some cases and as a "regular C pointer" in
other cases.
This change removes the conditional type defines and instead uses
void* everywhere. Explicit type casting in combination with ARC
annotations makes it safe to get typed Objective-C pointers from the
void* pointers.
This change enables ARC by default in the CEF binary distribution CMake
configuration for the cefclient and cefsimple sample applications. It can be
disabled by adding `-DOPTION_USE_ARC=Off` to the CMake command line.
ARC is not supported when building Chromium due to the substantial
number of changes that would be required in the Chromium code base.