Stop using DIST_DIR directly, use dist-for-goals instead

As a preparation in refactoring how we handle dist, I'm making
everything use dist-for-goals. In this case, instead of fully relying on
a phony rule, write the gtest xml into an intermediate folder, and use
dist-for-goals to copy that into the dist dir.

Bug: 117463001
Test: DIST_DIR=dist m aapt2_run_host_unit_tests dist
Test: DIST_DIR=dist m aapt2_run_host_unit_tests dist   (reruns test)
Change-Id: I166c2b3088703875c6028c3479aec7cf09f3f635
diff --git a/tools/aapt2/Android.mk b/tools/aapt2/Android.mk
index c9987b8..b165c6b 100644
--- a/tools/aapt2/Android.mk
+++ b/tools/aapt2/Android.mk
@@ -2,10 +2,19 @@
 
 include $(CLEAR_VARS)
 
+aapt2_results := $(call intermediates-dir-for,PACKAGING,aapt2_run_host_unit_tests)/result.xml
+
 # Target for running host unit tests on post/pre-submit.
 .PHONY: aapt2_run_host_unit_tests
-aapt2_run_host_unit_tests: PRIVATE_GTEST_OPTIONS := --gtest_output=xml:$(DIST_DIR)/gtest/aapt2_host_unit_tests_result.xml
-aapt2_run_host_unit_tests: $(HOST_OUT_NATIVE_TESTS)/aapt2_tests/aapt2_tests
-	-$(HOST_OUT_NATIVE_TESTS)/aapt2_tests/aapt2_tests $(PRIVATE_GTEST_OPTIONS) > /dev/null 2>&1
+aapt2_run_host_unit_tests: $(aapt2_results)
+
+$(call dist-for-goals,aapt2_run_host_unit_tests,$(aapt2_results):gtest/aapt2_host_unit_tests_result.xml)
+
+# Always run the tests again, even if they haven't changed
+$(aapt2_results): .KATI_IMPLICIT_OUTPUTS := $(aapt2_results)-nocache
+$(aapt2_results): $(HOST_OUT_NATIVE_TESTS)/aapt2_tests/aapt2_tests
+	-$(HOST_OUT_NATIVE_TESTS)/aapt2_tests/aapt2_tests --gtest_output=xml:$@ > /dev/null 2>&1
+
+aapt2_results :=
 
 include $(call all-makefiles-under,$(LOCAL_PATH))