Add support for prebuilt AARs.

- You can give a .aar as source file to a prebuilt static Java library
  module. The build system will set up dependencies and rules to extract
  classes.jar and other resource files.
- To build against a prebuilt AAR module, use:
  LOCAL_STATIC_JAVA_AAR_LIBRARIES := <module names of aar prebuilt AARs>
  The build system will set up rules to merge the library's
  AndroidManifest.xml with the main AndroidManifest.xml, add the AAR's
  resource dirs and link/merge the AAR's classes.jar.

Bug: 18168693
Change-Id: Ic2c1d20572a93bd98dbc72f8a39e26b459e442c2
(cherry picked from commit e9dd9f2bfceed3b5f630b0edbe3feb7f34548d8b)
diff --git a/core/android_manifest.mk b/core/android_manifest.mk
index 21b95c2..c641b75 100644
--- a/core/android_manifest.mk
+++ b/core/android_manifest.mk
@@ -11,13 +11,27 @@
   full_android_manifest := $(LOCAL_PATH)/$(LOCAL_MANIFEST_FILE)
 endif
 
+my_full_libs_manifest_files := $(LOCAL_FULL_LIBS_MANIFEST_FILES)
+my_full_libs_manifest_deps := $(LOCAL_FULL_LIBS_MANIFEST_FILES)
+
+# Set up dependency on aar libraries
+ifdef LOCAL_STATIC_JAVA_AAR_LIBRARIES
+my_full_libs_manifest_deps += $(foreach lib, $(LOCAL_STATIC_JAVA_AAR_LIBRARIES),\
+  $(call intermediates-dir-for,JAVA_LIBRARIES,$(lib),,COMMON)/aar/classes.jar)
+my_full_libs_manifest_files += $(foreach lib, $(LOCAL_STATIC_JAVA_AAR_LIBRARIES),\
+  $(call intermediates-dir-for,JAVA_LIBRARIES,$(lib),,COMMON)/aar/AndroidManifest.xml)
+
+LOCAL_RESOURCE_DIR += $(foreach lib, $(LOCAL_STATIC_JAVA_AAR_LIBRARIES),\
+  $(call intermediates-dir-for,JAVA_LIBRARIES,$(lib),,COMMON)/aar/res)
+endif
+
 # Set up rules to merge library manifest files
-ifdef LOCAL_FULL_LIBS_MANIFEST_FILES
+ifdef my_full_libs_manifest_files
 main_android_manifest := $(full_android_manifest)
 full_android_manifest := $(intermediates.COMMON)/AndroidManifest.xml
-$(full_android_manifest): PRIVATE_LIBS_MANIFESTS := $(LOCAL_FULL_LIBS_MANIFEST_FILES)
-$(full_android_manifest) : $(main_android_manifest) $(LOCAL_FULL_LIBS_MANIFEST_FILES)
-	@echo "Merge android manifest files: $@ <-- $^"
+$(full_android_manifest): PRIVATE_LIBS_MANIFESTS := $(my_full_libs_manifest_files)
+$(full_android_manifest) : $(main_android_manifest) $(my_full_libs_manifest_deps)
+	@echo "Merge android manifest files: $@ <-- $< $(PRIVATE_LIBS_MANIFESTS)"
 	@mkdir -p $(dir $@)
 	$(hide) $(ANDROID_MANIFEST_MERGER) --main $< --libs $(PRIVATE_LIBS_MANIFESTS) \
 	    --out $@