Export API files as part of the java_sdk_library

Bug: 153443117
Test: m nothing

Change-Id: I9d6f5b91a7cc25019e2eb9e3c138f0874d2831de

java/droiddoc.go

@@ -378,6 +378,7 @@ type ApiFilePath interface {
 // Provider of information about API stubs, used by java_sdk_library.
 type ApiStubsProvider interface {
 	ApiFilePath
+	RemovedApiFilePath() android.Path
 	StubsSrcJar() android.Path
 }
 
@@ -1266,6 +1267,10 @@ func (d *Droidstubs) ApiFilePath() android.Path {
 	return d.apiFilePath
 }
 
+func (d *Droidstubs) RemovedApiFilePath() android.Path {
+	return d.removedApiFile
+}
+
 func (d *Droidstubs) StubsSrcJar() android.Path {
 	return d.stubsSrcJar
 }