Skip unneeded notice files for ETC modules.

Non-installable, non-library modules can still have notice files
attached if they are bundled in an apex module, in which case the
current make setting would generate an error. This change makes it just
ignore them silently if the module is ETC. Other classes will still
trigger an error.

Test: manual build + TreeHugger
Change-Id: Ic7931f990369f744c8de62956a1a0a9c0451d6ab
diff --git a/core/notice_files.mk b/core/notice_files.mk
index e687ab2..c314734 100644
--- a/core/notice_files.mk
+++ b/core/notice_files.mk
@@ -38,6 +38,8 @@
 endif
 endif
 
+installed_notice_file :=
+
 ifdef notice_file
 
 ifdef my_register_name
@@ -71,12 +73,17 @@
       endif
       module_installed_filename := \
           $(patsubst $(PRODUCT_OUT)/%,%,$($(my_prefix)OUT_JAVA_LIBRARIES))/$(module_leaf)
+    else ifeq ($(LOCAL_MODULE_CLASS),ETC)
+      # ETC modules may be uninstallable, yet still have a NOTICE file. e.g. apex components
+      module_installed_filename :=
     else
       $(error Cannot determine where to install NOTICE file for $(LOCAL_MODULE))
     endif # JAVA_LIBRARIES
   endif # STATIC_LIBRARIES
 endif
 
+ifdef module_installed_filename
+
 # In case it's actually a host file
 module_installed_filename := $(patsubst $(HOST_OUT)/%,%,$(module_installed_filename))
 module_installed_filename := $(patsubst $(HOST_CROSS_OUT)/%,%,$(module_installed_filename))
@@ -110,10 +117,8 @@
 endif  # JAVA_LIBRARIES
 endif  # TARGET_BUILD_APPS
 
-else
-# NOTICE file does not exist
-installed_notice_file :=
-endif
+endif  # module_installed_filename
+endif  # notice_file
 
 # Create a predictable, phony target to build this notice file.
 # Define it even if the notice file doesn't exist so that other