Bug 1389718 fix receiving a message in proxy sandbox when running OOP, r=kmag

MozReview-Commit-ID: xgHIph36SG

--HG--
extra : rebase_source : 90010f086b713f7308d0f0367d96f6f79284b28a

toolkit/components/extensions/ExtensionParent.jsm

@@ -224,14 +224,14 @@ ProxyMessenger = {
       responseType,
     });
 
-    if (!extension.isEmbedded || !extension.remote) {
+    if (!(extension.isEmbedded || recipient.toProxyScript) || !extension.remote) {
       return promise1;
     }
 
-    // If we have a remote, embedded extension, the legacy side is
-    // running in a different process than the WebExtension side.
-    // As a result, we need to dispatch the message to both the parent
-    // and extension processes, and manually merge the results.
+    // If we have a proxy script sandbox or a remote, embedded extension, where
+    // the legacy side is running in a different process than the WebExtension
+    // side. As a result, we need to dispatch the message to both the parent and
+    // extension processes, and manually merge the results.
     let promise2 = MessageChannel.sendMessage(Services.ppmm.getChildAt(0), messageName, data, {
       sender,
       recipient,

toolkit/components/extensions/test/xpcshell/xpcshell-common.ini

@@ -69,3 +69,4 @@ skip-if = os == "android" # checking for telemetry needs to be updated: 1384923
 skip-if = os == "android"
 [test_native_messaging.js]
 skip-if = os == "android"
+[test_proxy_scripts.js]

toolkit/components/extensions/test/xpcshell/xpcshell.ini

@@ -52,7 +52,5 @@ tags = webextensions in-process-webextensions
 skip-if = os == "android" # Bug 1350559
 [test_ext_runtime_sendMessage_args.js]
 
-[test_proxy_scripts.js]
-
 [include:xpcshell-common.ini]
 [include:xpcshell-content.ini]