Add gen_notice module.

Refactor notices to support notices for multiple modules.

Enforce visibility and handle missing dependencies.

Bug: 213388645

Change-Id: Id6a81987f087419ad37d0cce57a71e8a7c4cd6e0
diff --git a/apex/builder.go b/apex/builder.go
index abbf8ad..f959b7a 100644
--- a/apex/builder.go
+++ b/apex/builder.go
@@ -618,7 +618,7 @@
 
 		// Create a NOTICE file, and embed it as an asset file in the APEX.
 		a.htmlGzNotice = android.PathForModuleOut(ctx, "NOTICE.html.gz")
-		android.BuildNoticeHtmlOutputFromLicenseMetadata(ctx, a.htmlGzNotice)
+		android.BuildNoticeHtmlOutputFromLicenseMetadata(ctx, a.htmlGzNotice, "", unsignedOutputFile.String())
 		noticeAssetPath := android.PathForModuleOut(ctx, "NOTICE", "NOTICE.html.gz")
 		builder := android.NewRuleBuilder(pctx, ctx)
 		builder.Command().Text("cp").