Add ART_USE_READ_BARRIER to product variables.

Bug: 33492005
Test: top-level build for angler.
Change-Id: I12aa2e18487c16423223f110b6dfb0d6dff1e7e8
diff --git a/core/product.mk b/core/product.mk
index e2a5339..93d42fd 100644
--- a/core/product.mk
+++ b/core/product.mk
@@ -127,6 +127,7 @@
     VENDOR_PRODUCT_RESTRICT_VENDOR_FILES \
     VENDOR_EXCEPTION_MODULES \
     VENDOR_EXCEPTION_PATHS \
+    PRODUCT_ART_USE_READ_BARRIER \
 
 
 
diff --git a/core/product_config.mk b/core/product_config.mk
index ea20bcb..295e263 100644
--- a/core/product_config.mk
+++ b/core/product_config.mk
@@ -423,3 +423,7 @@
     $(eval cf := $(subst $(_PSMC_SP_PLACE_HOLDER),$(space),$(cf)))\
     $(eval SANITIZER.$(TARGET_PRODUCT).$(m).CONFIG := $(cf))))
 _psmc_modules :=
+
+# Make this art variable visible to soong_config.mk.
+PRODUCT_ART_USE_READ_BARRIER := \
+    $(strip $(PRODUCTS.$(INTERNAL_PRODUCT).PRODUCT_ART_USE_READ_BARRIER))
diff --git a/core/soong_config.mk b/core/soong_config.mk
index 94cd4a0..f488566 100644
--- a/core/soong_config.mk
+++ b/core/soong_config.mk
@@ -62,7 +62,9 @@
 	echo '    "CrossHost": "$(HOST_CROSS_OS)",'; \
 	echo '    "CrossHostArch": "$(HOST_CROSS_ARCH)",'; \
 	echo '    "CrossHostSecondaryArch": "$(HOST_CROSS_2ND_ARCH)",'; \
-	echo '    "Safestack": $(if $(filter true,$(USE_SAFESTACK)),true,false)'; \
+	echo '    "Safestack": $(if $(filter true,$(USE_SAFESTACK)),true,false),'; \
+	echo ''; \
+	echo '    "ArtUseReadBarrier": $(if $(filter true,$(PRODUCT_ART_USE_READ_BARRIER)),true,false)'; \
 	echo '}') > $(SOONG_VARIABLES_TMP); \
 	if ! cmp -s $(SOONG_VARIABLES_TMP) $(SOONG_VARIABLES); then \
 	  mv $(SOONG_VARIABLES_TMP) $(SOONG_VARIABLES); \