Allow constructing aos::UUID from a span.

Change-Id: Ia676f0051841ffe2cc9441ef8aeed7a8f5bb0a85
Signed-off-by: James Kuszmaul <james.kuszmaul@bluerivertech.com>
diff --git a/aos/uuid.cc b/aos/uuid.cc
index ca429bf..67075b6 100644
--- a/aos/uuid.cc
+++ b/aos/uuid.cc
@@ -133,6 +133,14 @@
   return result;
 }
 
+UUID UUID::FromSpan(absl::Span<const uint8_t> data) {
+  CHECK_EQ(data.size(), kDataSize);
+
+  UUID result;
+  std::copy(data.begin(), data.end(), result.data_.begin());
+  return result;
+}
+
 UUID UUID::FromString(std::string_view str) {
   CHECK_EQ(str.size(), kStringSize);