Add ping_responder demo application

This allows us to easily track whether generated code will continue to
compile as we make changes (improvements) to aidl.

Bug: 25035409
Test: This code compiles

Change-Id: Ida69074c4f28e30dfd918792c282e18b8a2677f8
diff --git a/Android.mk b/Android.mk
index 483657d..9c02492 100644
--- a/Android.mk
+++ b/Android.mk
@@ -109,3 +109,29 @@
 endif # HOST_OS == linux
 
 endif # No TARGET_BUILD_APPS or TARGET_BUILD_PDK
+
+include $(CLEAR_VARS)
+LOCAL_MODULE := hellod
+LOCAL_C_INCLUDES := tests/ping_responder
+LOCAL_SRC_FILES := \
+    tests/ping_responder/aidl/android/os/IPingResponder.aidl \
+    tests/ping_responder/hellod.cpp
+LOCAL_SHARED_LIBRARIES := \
+    libbinder \
+    liblog \
+    libutils
+LOCAL_CFLAGS := -Wall -Wextra -Werror
+include $(BUILD_EXECUTABLE)
+
+include $(CLEAR_VARS)
+LOCAL_MODULE := helloc
+LOCAL_C_INCLUDES := tests/ping_responder
+LOCAL_SRC_FILES := \
+    tests/ping_responder/aidl/android/os/IPingResponder.aidl \
+    tests/ping_responder/helloc.cpp
+LOCAL_SHARED_LIBRARIES := \
+    libbinder \
+    liblog \
+    libutils
+LOCAL_CFLAGS := -Wall -Wextra -Werror
+include $(BUILD_EXECUTABLE)