Store AHWB in NN canonical memory type -- hal

Prior to this CL, the canonical memory type only held a SharedHandle,
which mirrors the behavior of native_handle_t/hidl_handle. This means
memory types including AHardwareBuffer were stored as this SharedHandle
type. With this CL, the canonical memory type is stored directly as
AHardwareBuffer to avoid using non-NDK AHardwareBuffer calls in the NN
runtime.

Bug: 179906132
Test: mma
Test: NeuralNetworksTest_static
Test: presubmit
Change-Id: I394071c193d15ac0c90ac47e5a2a9a79c635db6c
Merged-In: I394071c193d15ac0c90ac47e5a2a9a79c635db6c
(cherry picked from commit bbe43d950e981cfb5c06622c8f80b57ab60b0497)
diff --git a/neuralnetworks/1.2/utils/src/Conversions.cpp b/neuralnetworks/1.2/utils/src/Conversions.cpp
index 5055650..7ae483e 100644
--- a/neuralnetworks/1.2/utils/src/Conversions.cpp
+++ b/neuralnetworks/1.2/utils/src/Conversions.cpp
@@ -304,7 +304,11 @@
 }
 
 GeneralResult<SharedHandle> unvalidatedConvert(const hidl_handle& hidlHandle) {
-    return hal::utils::sharedHandleFromNativeHandle(hidlHandle.getNativeHandle());
+    if (hidlHandle.getNativeHandle() == nullptr) {
+        return nullptr;
+    }
+    auto handle = NN_TRY(hal::utils::sharedHandleFromNativeHandle(hidlHandle.getNativeHandle()));
+    return std::make_shared<const Handle>(std::move(handle));
 }
 
 GeneralResult<DeviceType> convert(const hal::V1_2::DeviceType& deviceType) {
@@ -588,7 +592,10 @@
 }
 
 nn::GeneralResult<hidl_handle> unvalidatedConvert(const nn::SharedHandle& handle) {
-    return hal::utils::hidlHandleFromSharedHandle(handle);
+    if (handle == nullptr) {
+        return {};
+    }
+    return hal::utils::hidlHandleFromSharedHandle(*handle);
 }
 
 nn::GeneralResult<DeviceType> convert(const nn::DeviceType& deviceType) {