Callback elision for HIDL interfaces.

Test: mma, hidl_test
Bug: 31380743
Change-Id: Ic5390d49a9493d1180bdd8a15bc47e891637890e
diff --git a/tests/inheritance/1.0/default/Fetcher.cpp b/tests/inheritance/1.0/default/Fetcher.cpp
index f3b576b..7094f07 100644
--- a/tests/inheritance/1.0/default/Fetcher.cpp
+++ b/tests/inheritance/1.0/default/Fetcher.cpp
@@ -17,8 +17,7 @@
     CHECK(!mPrecious->isRemote());
 }
 
-template <typename CB>
-Return<void> selectService(bool sendRemote, CB &_hidl_cb, sp<IChild> &local) {
+sp<IChild> selectService(bool sendRemote, sp<IChild> &local) {
     sp<IChild> toSend;
     if (sendRemote) {
         toSend = IChild::getService("child");
@@ -29,21 +28,20 @@
         toSend = local;
     }
     LOG(INFO) << "SERVER(Fetcher) selectService returning " << toSend.get();
-    _hidl_cb(toSend);
-    return Void();
+    return toSend;
 }
 
 // Methods from ::android::hardware::tests::inheritance::V1_0::IFetcher follow.
-Return<void> Fetcher::getGrandparent(bool sendRemote, getGrandparent_cb _hidl_cb)  {
-    return selectService(sendRemote, _hidl_cb, mPrecious);
+Return<sp<IGrandparent>> Fetcher::getGrandparent(bool sendRemote)  {
+    return selectService(sendRemote, mPrecious);
 }
 
-Return<void> Fetcher::getParent(bool sendRemote, getParent_cb _hidl_cb)  {
-    return selectService(sendRemote, _hidl_cb, mPrecious);
+Return<sp<IParent>> Fetcher::getParent(bool sendRemote)  {
+    return selectService(sendRemote, mPrecious);
 }
 
-Return<void> Fetcher::getChild(bool sendRemote, getChild_cb _hidl_cb)  {
-    return selectService(sendRemote, _hidl_cb, mPrecious);
+Return<sp<IChild>> Fetcher::getChild(bool sendRemote)  {
+    return selectService(sendRemote, mPrecious);
 }
 
 IFetcher* HIDL_FETCH_IFetcher(const char* /* name */) {
diff --git a/tests/inheritance/1.0/default/Fetcher.h b/tests/inheritance/1.0/default/Fetcher.h
index da9b153..979b47f 100644
--- a/tests/inheritance/1.0/default/Fetcher.h
+++ b/tests/inheritance/1.0/default/Fetcher.h
@@ -25,9 +25,9 @@
     Fetcher();
 
     // Methods from ::android::hardware::tests::inheritance::V1_0::IFetcher follow.
-    Return<void> getGrandparent(bool sendRemote, getGrandparent_cb _hidl_cb)  override;
-    Return<void> getParent(bool sendRemote, getParent_cb _hidl_cb)  override;
-    Return<void> getChild(bool sendRemote, getChild_cb _hidl_cb)  override;
+    Return<sp<IGrandparent>> getGrandparent(bool sendRemote)  override;
+    Return<sp<IParent>> getParent(bool sendRemote)  override;
+    Return<sp<IChild>> getChild(bool sendRemote)  override;
 
 private:
     sp<IChild> mPrecious;