Suppress the exception thrown when responding to message with no response callback.

chrome/browser/resources/hotword_helper/manager.js

 // Copyright (c) 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 'use strict';
 
 /**
  * @fileoverview This extension manages communications between Chrome,
  * Google.com pages and the Chrome Hotword extension.
  *
@@ skipping 14 matching lines @@
 
 
 /**
  * @const {string}
  * @private
  */
 OptInManager.HOTWORD_EXTENSION_ID_ = 'bepbmhgboaologfdajaanbcjmnhjmhfn';
 
 
 /**
+ * Test extension ID.
+ * @const {string}
+ * @private
+ */
+OptInManager.TEST_EXTENSION_ID_ = 'cpfhkdbjfdgdebcjlifoldbijinjfifp';
+
+
+/**
  * Commands sent from the page to this content script.
  * @enum {string}
  */
 OptInManager.CommandFromPage = {
   // User has explicitly clicked 'no'.
   CLICKED_NO_OPTIN: 'hcno',
   // User has opted in.
   CLICKED_OPTIN: 'hco',
   // Audio logging is opted in.
   AUDIO_LOGGING_ON: 'alon',
   // Audio logging is opted out.
   AUDIO_LOGGING_OFF: 'aloff',
   // User visited an eligible page.
   PAGE_WAKEUP: 'wu'
 };
 
 
 /**
  * @param {Tab} tab Tab to inject.
  * @param {function(HotwordStatus)} sendResponse Callback function to respond
  *     to sender.
  * @param {HotwordStatus} hotwordStatus Status of the hotword extension.
  * @private
  */
 OptInManager.prototype.injectTab_ = function(
     tab, sendResponse, hotwordStatus) {
-  if (tab.incognito || !hotwordStatus.available) {
-    sendResponse({'doNotShowOptinMessage': true});
-    return;
+  var response = {'doNotShowOptinMessage': true};
+
+  if (!(tab.incognito || !hotwordStatus.available)) {

[Dan Beam, 2014/09/24 04:58:27]

nit: if (!tab.incognito && hotwordState.available) {

[Anand Mistry (off Chromium), 2014/09/24 06:32:40]

Done.

+    if (!hotwordStatus.enabledSet)
+      response = hotwordStatus;
+    else if (hotwordStatus.enabled)
+      chrome.tabs.executeScript(tab.id, {'file': 'audio_client.js'});
   }
 
-  if (!hotwordStatus.enabledSet) {
-    sendResponse(hotwordStatus);
-    return;
+  try {
+    sendResponse(response);
+  } catch (err) {
+    // Suppress the exception thrown by sendResponse() when the page doesn't
+    // specify a response callback in the call to chrome.runtime.sendMessage().
+    // Unfortunately, there doesn't appear to be a way to detect one-way
+    // messages without explicitly saying in the message itself.  This message
+    // is defined as a constant in extensions/renderer/messaging_bindings.cc
+    if (err.message == 'Attempting to use a disconnected port object')
+      return;
+    throw err;
   }
-
-  if (hotwordStatus.enabled)
-    chrome.tabs.executeScript(tab.id, {'file': 'audio_client.js'});
-  sendResponse({'doNotShowOptinMessage': true});
 };
 
 
 /**
  * Handles messages from the helper content script.
  * @param {*} request Message from the sender.
  * @param {MessageSender} sender Information about the sender.
  * @param {function(HotwordStatus)} sendResponse Callback function to respond
  *     to sender.
  * @return {boolean} Whether to maintain the port open to call sendResponse.
  * @private
  */
 OptInManager.prototype.handleMessage_ = function(
     request, sender, sendResponse) {
   switch (request.type) {
     case OptInManager.CommandFromPage.PAGE_WAKEUP:
       if (((sender.tab && this.isEligibleUrl(sender.tab.url)) ||
-          sender.id == OptInManager.HOTWORD_EXTENSION_ID_) &&
+          sender.id == OptInManager.HOTWORD_EXTENSION_ID_ ||
+          sender.id == OptInManager.TEST_EXTENSION_ID_) &&
           chrome.hotwordPrivate && chrome.hotwordPrivate.getStatus) {
         chrome.hotwordPrivate.getStatus(
-            this.injectTab_.bind(this, request.tab || sender.tab,
-                                 sendResponse));
+            this.injectTab_.bind(
+                this,
+                request.tab || sender.tab || {incognito: true},
+                sendResponse));
         return true;
       }
       break;
     case OptInManager.CommandFromPage.CLICKED_OPTIN:
       if (chrome.hotwordPrivate && chrome.hotwordPrivate.setEnabled &&
           chrome.hotwordPrivate.getStatus) {
         chrome.hotwordPrivate.setEnabled(true);
         chrome.hotwordPrivate.getStatus(
             this.injectTab_.bind(this, sender.tab, sendResponse));
         return true;
@@ skipping 98 matching lines @@
   // TODO(rlp): Possibly remove the next line. It's proably not used, but
   // leaving for now to be safe. We should remove it once all messsage
   // relaying is removed form the content scripts.
   chrome.runtime.onMessage.addListener(this.handleMessage_.bind(this));
   chrome.runtime.onMessageExternal.addListener(
       this.handleMessage_.bind(this));
 };
 
 
 new OptInManager().initialize();