use init functions to register module types, etc.

Instead of putting all the blueprint registrations in soong_build,
put them all in init() functions.  This puts the registration next
to the implementation.

Change-Id: Ide1a749518f5e9d1367a18ab3bb1d91da3310c76

java/java.go

@@ -26,10 +26,24 @@ import (
 	"github.com/google/blueprint"
 	"github.com/google/blueprint/pathtools"
 
+	"android/soong"
 	"android/soong/common"
 	"android/soong/genrule"
 )
 
+func init() {
+	soong.RegisterModuleType("java_library", JavaLibraryFactory)
+	soong.RegisterModuleType("java_library_static", JavaLibraryFactory)
+	soong.RegisterModuleType("java_library_host", JavaLibraryHostFactory)
+	soong.RegisterModuleType("java_binary", JavaBinaryFactory)
+	soong.RegisterModuleType("java_binary_host", JavaBinaryHostFactory)
+	soong.RegisterModuleType("prebuilt_java_library", JavaPrebuiltFactory)
+	soong.RegisterModuleType("prebuilt_sdk", SdkPrebuiltFactory)
+	soong.RegisterModuleType("android_app", AndroidAppFactory)
+
+	soong.RegisterSingletonType("logtags", LogtagsSingleton)
+}
+
 // TODO:
 // Autogenerated files:
 //  Proto