Protect all uses of JSON.parse against exceptions.

remoting/webapp/client_plugin_async.js

Index: remoting/webapp/client_plugin_async.js
diff --git a/remoting/webapp/client_plugin_async.js b/remoting/webapp/client_plugin_async.js
index b0baec36d3deda87223cafb2130698777b9b3dbd..43b111022a465b71e08b22999bbe74fd69418b87 100644
--- a/remoting/webapp/client_plugin_async.js
+++ b/remoting/webapp/client_plugin_async.js
@@ -87,11 +87,11 @@ remoting.ClientPluginAsync.prototype.API_MIN_VERSION_ = 5;
 /**
  * @param {string} message_str Message from the plugin.
  */
-remoting.ClientPluginAsync.prototype.handleMessage_ = function(message_str) {
+remoting.ClientPluginAsync.prototype.handleMessage_ = function(messageStr) {
   var message = /** @type {{method:string, data:Object.<string,string>}} */
-      JSON.parse(message_str);
+      jsonParseSafe(messageStr);
 
-  if (!('method' in message) || !('data' in message)) {
+  if (!message || !('method' in message) || !('data' in message)) {
     console.error('Received invalid message from the plugin: ' + message_str);
     return;
   }