Re-enable dx support

This is a partial revert of commits:
858657366fa6 Remove support of disabling Jack.
3ae78612522e Remove javac support in host dex rules.
22313f2b2a4a Remove rules for building dex with dx

Test: builds
Change-Id: Ie12d743cbe978bdeb030910848b67f5945a4fec8
diff --git a/core/java_library.mk b/core/java_library.mk
index b132fa6..f770a54 100644
--- a/core/java_library.mk
+++ b/core/java_library.mk
@@ -29,9 +29,11 @@
 include $(BUILD_SYSTEM)/configure_local_jack.mk
 #################################
 
+ifdef LOCAL_JACK_ENABLED
 ifdef LOCAL_IS_STATIC_JAVA_LIBRARY
 LOCAL_BUILT_MODULE_STEM := classes.jack
 endif
+endif
 
 intermediates.COMMON := $(call local-intermediates-dir,COMMON)
 
@@ -46,8 +48,12 @@
 ifeq (true,$(EMMA_INSTRUMENT))
 ifeq (true,$(LOCAL_EMMA_INSTRUMENT))
 ifeq (true,$(EMMA_INSTRUMENT_STATIC))
+ifdef LOCAL_JACK_ENABLED
 # Jack supports coverage with Jacoco
 LOCAL_STATIC_JAVA_LIBRARIES += jacocoagent
+else
+LOCAL_STATIC_JAVA_LIBRARIES += emma
+endif # LOCAL_JACK_ENABLED
 endif # LOCAL_EMMA_INSTRUMENT
 endif # EMMA_INSTRUMENT_STATIC
 else
@@ -61,21 +67,37 @@
 ifeq ($(LOCAL_IS_STATIC_JAVA_LIBRARY),true)
 # No dex; all we want are the .class files with resources.
 $(common_javalib.jar) : $(java_resource_sources)
+ifdef LOCAL_PROGUARD_ENABLED
+$(common_javalib.jar) : $(full_classes_proguard_jar)
+else
 $(common_javalib.jar) : $(full_classes_jar)
+endif
 	@echo "target Static Jar: $(PRIVATE_MODULE) ($@)"
 	$(copy-file-to-target)
 
+ifdef LOCAL_JACK_ENABLED
 $(LOCAL_BUILT_MODULE) : $(full_classes_jack)
+else
+$(LOCAL_BUILT_MODULE) : $(common_javalib.jar)
+endif
 	$(copy-file-to-target)
 
 else # !LOCAL_IS_STATIC_JAVA_LIBRARY
 
 $(common_javalib.jar): PRIVATE_DEX_FILE := $(built_dex)
+$(common_javalib.jar): PRIVATE_SOURCE_ARCHIVE := $(full_classes_jarjar_jar)
+$(common_javalib.jar): PRIVATE_DONT_DELETE_JAR_DIRS := $(LOCAL_DONT_DELETE_JAR_DIRS)
 $(common_javalib.jar) : $(built_dex) $(java_resource_sources) | $(ZIPTIME)
 	@echo "target Jar: $(PRIVATE_MODULE) ($@)"
+ifdef LOCAL_JACK_ENABLED
 	$(create-empty-package)
+else
+	$(call initialize-package-file,$(PRIVATE_SOURCE_ARCHIVE),$@)
+endif
 	$(add-dex-to-package)
+ifdef LOCAL_JACK_ENABLED
 	$(add-carried-jack-resources)
+endif
 	$(remove-timestamps-from-package)
 
 ifdef LOCAL_DEX_PREOPT