Move private_manifest file insertion to jars merging phase.

By doing this, the change of private_manifest file won't trigger
Javac to re-run during re-build.

Bug: b/65455145
Test: m clean && m -j32
Change-Id: Ib90d56daf0be5f31b51e07b7714a933bc5cf4496
diff --git a/core/host_java_library.mk b/core/host_java_library.mk
index 55b6684..03dc67c 100644
--- a/core/host_java_library.mk
+++ b/core/host_java_library.mk
@@ -82,7 +82,6 @@
     $(java_source_list_file) \
     $(java_sources_deps) \
     $(full_java_libs) \
-    $(jar_manifest_file) \
     $(annotation_processor_deps) \
     $(NORMALIZE_PATH) \
     $(ZIPTIME) \
@@ -95,8 +94,12 @@
 javac-check-$(LOCAL_MODULE) : $(full_classes_compiled_jar)
 
 $(full_classes_combined_jar): $(full_classes_compiled_jar) \
+                              $(jar_manifest_file) \
                               $(full_static_java_libs) | $(MERGE_ZIPS)
-	$(MERGE_ZIPS) -j -stripDir META-INF -zipToNotStrip $< $@ $< $(call reverse-list,$(PRIVATE_STATIC_JAVA_LIBRARIES))
+	$(if $(PRIVATE_JAR_MANIFEST), $(hide) sed -e "s/%BUILD_NUMBER%/$(BUILD_NUMBER_FROM_FILE)/" \
+            $(PRIVATE_JAR_MANIFEST) > $(dir $@)/manifest.mf)
+	$(MERGE_ZIPS) -j $(if $(PRIVATE_JAR_MANIFEST),-m $(dir $@)/manifest.mf) \
+            -stripDir META-INF -zipToNotStrip $< $@ $< $(call reverse-list,$(PRIVATE_STATIC_JAVA_LIBRARIES))
 
 # Run jarjar if necessary, otherwise just copy the file.
 ifneq ($(strip $(LOCAL_JARJAR_RULES)),)