Callback elision for HIDL interfaces.

Test: mma, hidl_test
Bug: 31380743
Change-Id: If5f0dc0279e717dafaf416776be89cc854c6f856
diff --git a/libhidlmemory/mapping.cpp b/libhidlmemory/mapping.cpp
index b4fa123..3761f99 100644
--- a/libhidlmemory/mapping.cpp
+++ b/libhidlmemory/mapping.cpp
@@ -40,19 +40,14 @@
         LOG(FATAL) << "IMapper must be a passthrough service.";
     }
 
-    sp<IMemory> retMemory = nullptr;
-
-    Return<void> ret = mapper->mapMemory(memory,
-        [&retMemory](const auto &mapped) {
-            retMemory = mapped;
-        });
+    Return<sp<IMemory>> ret = mapper->mapMemory(memory);
 
     if (!ret.isOk()) {
         LOG(FATAL) << "hidl_memory map returned transport error.";
     }
 
-    return retMemory;
+    return ret;
 }
 
 }  // namespace hardware
-}  // namespace android
\ No newline at end of file
+}  // namespace android