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

chrome/browser/resources/hotword_helper/manager.js

Index: chrome/browser/resources/hotword_helper/manager.js
diff --git a/chrome/browser/resources/hotword_helper/manager.js b/chrome/browser/resources/hotword_helper/manager.js
index 4ce86db62959d7fb42ade923a8d80fb11daa24f2..7544d35a95fcf35ddfca933facf9a28419357782 100644
--- a/chrome/browser/resources/hotword_helper/manager.js
+++ b/chrome/browser/resources/hotword_helper/manager.js
@@ -32,6 +32,14 @@ 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}
  */
@@ -58,19 +66,27 @@ OptInManager.CommandFromPage = {
  */
 OptInManager.prototype.injectTab_ = function(
     tab, sendResponse, hotwordStatus) {
-  if (tab.incognito || !hotwordStatus.available) {
-    sendResponse({'doNotShowOptinMessage': true});
-    return;
-  }
+  var response = {'doNotShowOptinMessage': true};
 
-  if (!hotwordStatus.enabledSet) {
-    sendResponse(hotwordStatus);
-    return;
+  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.enabled)
-    chrome.tabs.executeScript(tab.id, {'file': 'audio_client.js'});
-  sendResponse({'doNotShowOptinMessage': true});
+  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;
+  }
 };
 
 
@@ -88,11 +104,14 @@ OptInManager.prototype.handleMessage_ = function(
   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;