Translate: Don't use custom CSS and JavaScript loader on iOS

Custom JavaScript loader doesn't work on iOS because an origin check
fails outside v8 isolated world. Chrome should not overwrite these
callbacks on iOS.

BUG=none
TEST=none

Review URL: https://chromiumcodereview.appspot.com/23715006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@222254 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/translate/translate_script.cc

@@ -88,6 +88,8 @@ void TranslateScript::Request(const Callback& callback) {
       translate_script_url,
       kAlwaysUseSslQueryName,
       kAlwaysUseSslQueryValue);
+#if !defined(OS_IOS)
+  // iOS doesn't need to use specific loaders for the isolated world.
   translate_script_url = net::AppendQueryParameter(
       translate_script_url,
       kCssLoaderCallbackQueryName,
@@ -96,6 +98,7 @@ void TranslateScript::Request(const Callback& callback) {
       translate_script_url,
       kJavascriptLoaderCallbackQueryName,
       kJavascriptLoaderCallbackQueryValue);
+#endif  // !defined(OS_IOS)
 
   translate_script_url =
       TranslateURLUtil::AddHostLocaleToUrl(translate_script_url);