Previously the loader would destroy any debug callbacks created during instance creation
to later create new ones during instance destruction. This required a memory allocation
to occur inside vkDestroyInstance, which can cause leaks if an OOM occurs during
instance destruction.
This commit simplifies the logic by keeping around the allocations made during instance
creation by moving them into their own debug node chain. Then during instance destruction
moves them back.
Also renames several functions to better describe their intended purpose.
This commit separates the structure definitions from the function declarations.
The reason to do this is to allow splitting of loader.h/.c functionality into
individual headers, which may require access to these structs but don't need to
know about the other functions.
This affects the loader, scripts, and layers and introduces the
changes to support the VK_EXT_debug_utils extension.
Change-Id: Ia5336f63e85b00f1e59416c06aacd4ae331fd692
andrew0229