SkTLogic.h contains implemenetations of is_empty, is_class, decay,
decay_t, add_lvalue_reference, add_rvalue_reference, and
add_rvalue_reference_t. The declaration of is_class is only used by
is_empty. The current implementation of is_empty will not work
correctly with 'final'. The current implementation of
add_lvalue_reference does not support clarifications in c++17. No Skia
code is currently using decay, decay_t, add_rvalue_reference, and
add_rvalue_reference_t. In addition, there are no known issues with
any of these in ::std with any supported compiler.
The implementations of is_function and is_convertible are commented to
note why they are still present.
Review URL: https://codereview.chromium.org/1567123006
0e101667d6