Fix "MojoInterfaceInterceptor is not defined" error

which causes the promise being rejected and testharness reports error given
that there are unhandled rejected promises

Differential Revision: https://phabricator.services.mozilla.com/D32071

bugzilla-url: https://bugzilla.mozilla.org/show_bug.cgi?id=1525554
gecko-commit: 67cd5b8663cadce188e15fa2146bd875c17b82bd
gecko-integration-branch: autoland
gecko-reviewers: annevk

Author: moz-wptsync-bot

mediacapture-image/resources/imagecapture-helpers.js

@@ -10,7 +10,7 @@
 //   --enable-blink-features=MojoJS,MojoJSTest
 
 let loadChromiumResources = Promise.resolve().then(() => {
-  if (!MojoInterfaceInterceptor) {
+  if (!('MojoInterfaceInterceptor' in self)) {
     // Do nothing on non-Chromium-based browsers or when the Mojo bindings are
     // not present in the global namespace.
     return;

shape-detection/resources/shapedetection-helpers.js

@@ -10,7 +10,7 @@
 //   --enable-blink-features=MojoJS,MojoJSTest
 
 let loadChromiumResources = Promise.resolve().then(() => {
-  if (!MojoInterfaceInterceptor) {
+  if (!('MojoInterfaceInterceptor' in self)) {
     // Do nothing on non-Chromium-based browsers or when the Mojo bindings are
     // not present in the global namespace.
     return;

webxr/resources/webxr_util.js

@@ -116,7 +116,7 @@ function forEachWebxrObject(callback) {
 
 // Code for loading test api in chromium.
 let loadChromiumResources = Promise.resolve().then(() => {
-  if (!MojoInterfaceInterceptor) {
+  if (!('MojoInterfaceInterceptor' in self)) {
     // Do nothing on non-Chromium-based browsers or when the Mojo bindings are
     // not present in the global namespace.
     return;