Merge changes from topic "hiddenapi_exportable" into main

* changes:
  Copy exportable artifacts to module sdk snapshot
  Enable hiddenapi check for exportable stubs
  Add defaults support for bootclasspath_fragment module type

java/droidstubs.go

@@ -199,6 +199,10 @@ type ApiStubsSrcProvider interface {
 	StubsSrcJar() android.Path
 }
 
+type ExportableApiStubsSrcProvider interface {
+	ExportableStubsSrcJar() android.Path
+}
+
 // Provider of information about API stubs, used by java_sdk_library.
 type ApiStubsProvider interface {
 	AnnotationsZip() android.Path
@@ -208,6 +212,14 @@ type ApiStubsProvider interface {
 	ApiStubsSrcProvider
 }
 
+type ExportableApiStubsProvider interface {
+	ExportableAnnotationsZip() android.Path
+	ExportableApiFilePath() android.Path
+	ExportableRemovedApiFilePath() android.Path
+
+	ExportableApiStubsSrcProvider
+}
+
 type currentApiTimestampProvider interface {
 	CurrentApiTimestamp() android.Path
 }