[ios] Do not JSON encode messages sent from WebView to native code.

ios/web/web_state/js/resources/message.js

Index: ios/web/web_state/js/resources/message.js
diff --git a/ios/web/web_state/js/resources/message.js b/ios/web/web_state/js/resources/message.js
index 47d32a78c24a6fb9bca96fc1a6531bf39584cc79..96dc9ad2f01d5017c4741351a91b48ef1fd4d7d7 100644
--- a/ios/web/web_state/js/resources/message.js
+++ b/ios/web/web_state/js/resources/message.js
@@ -77,17 +77,15 @@ __gCrWeb['message'] = __gCrWeb.message;
       delete Object.prototype.toJSON;
 
     queueObject.queue.forEach(function(command) {
-        var stringifiedMessage = __gCrWeb.common.JSONStringify({
-            "crwCommand": command,
-            "crwWindowId": __gCrWeb['windowId']
-        });
         // A web page can override |window.webkit| with any value. Deleting the
         // object ensures that original and working implementation of
         // window.webkit is restored.
         var oldWebkit = window.webkit;
         delete window['webkit'];
-        window.webkit.messageHandlers[queueObject.scheme].postMessage(
-            stringifiedMessage);
+        window.webkit.messageHandlers[queueObject.scheme].postMessage({
+            "crwCommand": command,
+            "crwWindowId": __gCrWeb['windowId']
+        });
         window.webkit = oldWebkit;
     });
     queueObject.reset();