Share the platform-neutral Rust mobile contract (#91)

tools/android-build/src/bindings.rs

@@ -61,14 +61,14 @@ fn harden_source(source: &str) -> Result<String, Box<dyn Error>> {
     }
     let source = source.replace(internal, "class InternalException(@Suppress(\"UNUSED_PARAMETER\") message: String) : kotlin.Exception(\"Native Rust failure ([REDACTED])\")")
         .replace(callback, "val err = \"Native callback failed ([REDACTED])\"");
-    let records = Regex::new(r"(?ms)^data class (\w+) \((.*?)\n\)([^\{]*)\{\n")?;
+    let records = Regex::new(r"(?ms)^([ \t]*)data class (\w+)\s*\((.*?)\)[^\{]*\{\n")?;
     if !records.is_match(&source) {
         return Err("UniFFI record template changed; review diagnostic hardening".into());
     }
     let source = records.replace_all(&source, |captures: &regex::Captures<'_>| {
         format!(
             "{}    override fun toString(): String = \"{}([REDACTED])\"\n",
-            &captures[0], &captures[1]
+            &captures[0], &captures[2]
         )
     });
     let errors = Regex::new(r#"(?m)(override val message\n\s*)get\(\) = ".*"$"#)?;