Prevent extensions from clobbering JSON implementation that extension calls use

chrome/test/data/extensions/api_test/messaging/connect/page.js

Index: chrome/test/data/extensions/api_test/messaging/connect/page.js
diff --git a/chrome/test/data/extensions/api_test/messaging/connect/page.js b/chrome/test/data/extensions/api_test/messaging/connect/page.js
index b876f7ef40c9ab2b7ef8b91e8ee8c0f107b3f5a7..9d45f6417b0ccf6f71f364979a2ff59a6f62c3e7 100644
--- a/chrome/test/data/extensions/api_test/messaging/connect/page.js
+++ b/chrome/test/data/extensions/api_test/messaging/connect/page.js
@@ -1,3 +1,19 @@
+JSON.parse = function() {
+  return "JSON.parse clobbered by content script.";
+}
+
+JSON.stringify = function() {
+  return "JSON.stringify clobbered by content script.";
+}
+
+Array.prototype.toJSON = function() {
+  return "Array.prototype.toJSON clobbered by content script.";
+}
+
+Object.prototype.toJSON = function() {
+  return "Object.prototype.toJSON clobbered by content script.";
+}
+
 // For complex connect tests.
 chrome.extension.onConnect.addListener(function(port) {
   console.log('connected');