vulkan-cereal: external Vulkan memory for gfxstream + vhost-user

This adds initial external memory support for gfxstream, so when
Cuttlefish and friends transition to vhost-user, the virtio-gpu
device will relatively ready.

There are a few other things to do:

Namely:

   - Cross platform abstrations rather than #ifdef everywhere
   - Windows support
   - Should we use UUIDs instead of physical device index?
   - Should we nuke memory_index and rely on vkGetMemoryFdPropertiesKHR
     instead?
   - Passing in VkExternalMemoryBufferCreateInfo or
     VkExternalMemoryImageCreateInfo if the validation layers
     complains about it's absence

BUG=235485545
TEST=compile and run

Change-Id: I9858892fdfe16a785d990ce44cd09b68815c80cf

1 files changed, 6 insertions, 0 deletions

diff --git a/base/include/base/ManagedDescriptor.hpp b/base/include/base/ManagedDescriptor.hpp
index db43188..0dfb406 100644
--- a/base/include/base/ManagedDescriptor.hpp
+++ b/base/include/base/ManagedDescriptor.hpp
@@ -37,6 +37,10 @@ struct PlatformTraitUnixLike {
 #endif
 }  // namespace internal
 
+
+template <class PlatformTrait>
+using DescriptorTypeBase = typename PlatformTrait::DescriptorType;
+
 // An RAII wrapper for fd on *nix or HANDLE on Windows. The interfaces are similar to std::unique.
 template <class PlatformTrait>
 class ManagedDescriptorBase {
@@ -94,8 +98,10 @@ class ManagedDescriptorBase {
 };
 
 #ifdef _WIN32
+using DescriptorType = DescriptorTypeBase<internal::PlatformTraitWin32>;
 using ManagedDescriptor = ManagedDescriptorBase<internal::PlatformTraitWin32>;
 #elif defined(__APPLE__) || defined(__linux__)
+using DescriptorType = DescriptorTypeBase<internal::PlatformTraitUnixLike>;
 using ManagedDescriptor = ManagedDescriptorBase<internal::PlatformTraitUnixLike>;
 #endif