Improve commenting for cc/builer.go, and kill dead code

Test: m nothing
Change-Id: I836c717d3243e901257120be71246e419de4d28e
diff --git a/cc/vendor_snapshot.go b/cc/vendor_snapshot.go
index 6563f6e..94f859e 100644
--- a/cc/vendor_snapshot.go
+++ b/cc/vendor_snapshot.go
@@ -339,7 +339,7 @@
 		// depending on a table of contents file instead of the library itself.
 		tocFile := android.PathForModuleOut(ctx, libName+".toc")
 		p.tocFile = android.OptionalPathForPath(tocFile)
-		TransformSharedObjectToToc(ctx, in, tocFile, builderFlags)
+		transformSharedObjectToToc(ctx, in, tocFile, builderFlags)
 
 		ctx.SetProvider(SharedLibraryInfoProvider, SharedLibraryInfo{
 			SharedLibrary:           in,