[ObjC ARC] Converts ios/web/public/test:test to ARC.

ios/web/public/test/js_test_util.h

Index: ios/web/public/test/js_test_util.h
diff --git a/ios/web/public/test/js_test_util.h b/ios/web/public/test/js_test_util.h
index ea21a5098a0ed6ab97ea5962312a2a35438af346..c7b1e80de4369ee7e1d14f5632b79e43f54e9a1b 100644
--- a/ios/web/public/test/js_test_util.h
+++ b/ios/web/public/test/js_test_util.h
@@ -27,7 +27,11 @@ id ExecuteJavaScript(CRWJSInjectionReceiver* receiver, NSString* script);
 
 // Executes JavaScript on |web_view| and returns the result as an id.
 // |error| can be null and will be updated only if script execution fails.
-id ExecuteJavaScript(WKWebView* web_view, NSString* script, NSError** error);
+// TODO(crbug.com/730062): Remove __unsafe_unretained when all callers are
+// are converted to ARC.

[baxley, 2017/06/06 17:16:48]

Here's an example where this was done in another file:
https://codereview.chromium.org/2684023003/diff/20001/ios/chrome/test/earl_gr...

+id ExecuteJavaScript(WKWebView* web_view,
+                     NSString* script,
+                     NSError* __unsafe_unretained* error);
 
 // Executes JavaScript on |web_view| and returns the result as an id.
 // Fails if there was an error during script execution.