Bug 1535661 - Fix CORS issues in Markup Panel r=pbro

One change is in `node.js::isScrollable()` so I decided to assign this to you for review. Feel free to re-assign as you feel appropriate if you don't have time.

### Try

https://treeherder.mozilla.org/#/jobs?repo=try&revision=2e2f20af3f902ea65436bcfd288b3e075d6508f8

Differential Revision: https://phabricator.services.mozilla.com/D23803

--HG--
extra : moz-landing-system : lando

devtools/server/actors/inspector/event-collector.js

@@ -265,7 +265,15 @@ class MainEventCollector {
   }
 
   getJQuery(node) {
+    if (Cu.isDeadWrapper(node)) {
+      return null;
+    }
+
     const global = this.unwrap(node.ownerGlobal);
+    if (!global) {
+      return null;
+    }
+
     const hasJQuery = global.jQuery && global.jQuery.fn && global.jQuery.fn.jquery;
 
     if (hasJQuery) {
@@ -390,14 +398,25 @@ class JQueryEventCollector extends MainEventCollector {
     }
 
     let eventsObj = null;
-
     const data = jQuery._data || jQuery.data;
+
     if (data) {
       // jQuery 1.2+
-      eventsObj = data(node, "events");
+      try {
+        eventsObj = data(node, "events");
+      } catch (e) {
+        // We have no access to a JS object. This is probably due to a CORS
+        // violation. Using try / catch is the only way to avoid this error.
+      }
     } else {
       // JQuery 1.0 & 1.1
-      const entry = jQuery(node)[0];
+      let entry;
+      try {
+        entry = entry = jQuery(node)[0];
+      } catch (e) {
+        // We have no access to a JS object. This is probably due to a CORS
+        // violation. Using try / catch is the only way to avoid this error.
+      }
 
       if (!entry || !entry.events) {
         if (checkOnly) {
@@ -474,7 +493,14 @@ class JQueryLiveEventCollector extends MainEventCollector {
       // Any element matching the specified selector will trigger the live
       // event.
       const win = this.unwrap(node.ownerGlobal);
-      const events = data(win.document, "events");
+      let events = null;
+
+      try {
+        events = data(win.document, "events");
+      } catch (e) {
+        // We have no access to a JS object. This is probably due to a CORS
+        // violation. Using try / catch is the only way to avoid this error.
+      }
 
       if (events) {
         for (const [, eventHolder] of Object.entries(events)) {

devtools/server/actors/inspector/node.js

@@ -262,9 +262,15 @@ const NodeActor = protocol.ActorClassWithSpec(nodeSpec, {
     }
 
     // If it does, then check it also has scrollbars.
-    const walker = new DocumentWalker(this.rawNode, this.rawNode.ownerGlobal,
-                                      { filter: scrollbarTreeWalkerFilter });
-    return !!walker.firstChild();
+    try {
+      const walker = new DocumentWalker(this.rawNode, this.rawNode.ownerGlobal,
+                                        { filter: scrollbarTreeWalkerFilter });
+      return !!walker.firstChild();
+    } catch (e) {
+      // We have no access to a DOM object. This is probably due to a CORS
+      // violation. Using try / catch is the only way to avoid this error.
+      return false;
+    }
   },
 
   /**
@@ -340,6 +346,10 @@ const NodeActor = protocol.ActorClassWithSpec(nodeSpec, {
     // Get a reference to the custom element definition function.
     const name = this.rawNode.localName;
 
+    if (!this.rawNode.ownerGlobal) {
+      return undefined;
+    }
+
     const customElementsRegistry = this.rawNode.ownerGlobal.customElements;
     const customElement = customElementsRegistry && customElementsRegistry.get(name);
     if (!customElement) {