Change NNAPI time from steady_clock to boot_clock -- hal

Previously, the NNAPI used std::chrono::steady_clock to represent and
measure timings. However, steady_clock does not count while the system
is suspended. Instead, boot_clock is monotonic like steady_clock but
does include the time when the system is suspended.

This change also indicates that services may convert from
std::chrono::steady_clock::time_point to
android::base::boot_clock::time_point in the HIDL 1.3 NN HAL.

Bug: 183118340
Test: mma
Test: VtsHalNeuralnetworksV1_3TargetTest
Test: VtsHalNeuralnetworksTargetTest
Test: presubmit
Change-Id: I5a7d039a31d9ce98602a301387ec99635f279f42
Merged-In: I5a7d039a31d9ce98602a301387ec99635f279f42
(cherry picked from commit b8cf54cf5a5dc1639364cc6d79cc986efa6dceab)
diff --git a/neuralnetworks/aidl/utils/src/Conversions.cpp b/neuralnetworks/aidl/utils/src/Conversions.cpp
index c74c509..d5f7f81 100644
--- a/neuralnetworks/aidl/utils/src/Conversions.cpp
+++ b/neuralnetworks/aidl/utils/src/Conversions.cpp
@@ -931,11 +931,12 @@
 }
 
 nn::GeneralResult<int64_t> unvalidatedConvert(const nn::Duration& duration) {
-    const uint64_t nanoseconds = duration.count();
-    if (nanoseconds > std::numeric_limits<int64_t>::max()) {
-        return std::numeric_limits<int64_t>::max();
+    if (duration < nn::Duration::zero()) {
+        return NN_ERROR() << "Unable to convert invalid (negative) duration";
     }
-    return static_cast<int64_t>(nanoseconds);
+    constexpr std::chrono::nanoseconds::rep kIntMax = std::numeric_limits<int64_t>::max();
+    const auto count = duration.count();
+    return static_cast<int64_t>(std::min(count, kIntMax));
 }
 
 nn::GeneralResult<int64_t> unvalidatedConvert(const nn::OptionalDuration& optionalDuration) {