Collect and store proguard obfuscation dictionary files.

Collect and store proguard obfuscation dictionary files.
Only do this for apps_only build for now.

Bug: 9407666
Change-Id: I51c78bf0f42f959dc920de230e60e0f71ed0d0ea
diff --git a/core/Makefile b/core/Makefile
index 55ab6a5..6c57a49 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -1391,6 +1391,24 @@
 
 endif # EMMA_INSTRUMENT=true
 
+#------------------------------------------------------------------
+# A zip of Proguard obfuscation dictionary files.
+# Only for apps_only build.
+#
+ifdef TARGET_BUILD_APPS
+PROGUARD_DICT_ZIP := $(PRODUCT_OUT)/proguard-dict-$(FILE_NAME_TAG).zip
+# the dependency will be set up later in build/core/main.mk.
+$(PROGUARD_DICT_ZIP) :
+	@echo "Packaging Proguard obfuscation dictionary files."
+	$(hide) dict_files=`find $(TARGET_OUT_COMMON_INTERMEDIATES)/APPS -name proguard_dictionary`; \
+		if [ -n "$$dict_files" ]; then \
+		  zip -q $@ $$dict_files; \
+		else \
+		  touch $@; \
+		fi
+
+endif # TARGET_BUILD_APPS
+
 # -----------------------------------------------------------------
 # dalvik something
 .PHONY: dalvikfiles