Bug 1532795: Part 5 - Support SpecialPowers.spawn on WindowProxy objects. r=nika

Differential Revision: https://phabricator.services.mozilla.com/D35378

--HG--
extra : rebase_source : c69b88bd7142f70612c05e56e1a0d690b464ff99
extra : source : d5415970da5fd83eb870b397b8db7fdf6c57ad23

testing/mochitest/tests/Harness_sanity/test_SpecialPowersSpawn.html

@@ -9,6 +9,8 @@
 
 <iframe id="iframe"></iframe>
 
+<span id="hello">World.</span>
+
 <script>
 /* eslint-disable prettier/prettier */
 /* globals SpecialPowers, content */
@@ -26,7 +28,31 @@
       return elem.textContent;
     });
 
-    is(result, "Hello there.", "Got correct element text");
+    is(result, "Hello there.", "Got correct element text from frame");
+
+    result = await SpecialPowers.spawn(frame, ["#hello"], selector => {
+      return SpecialPowers.spawn(content.parent, [selector], selector => {
+        let elem = content.document.querySelector(selector);
+        return elem.textContent;
+      });
+    });
+
+    is(result, "World.", "Got correct element text from frame's window.parent");
+
+    result = await SpecialPowers.spawn(frame.contentWindow, ["#span"], selector => {
+      let elem = content.document.querySelector(selector);
+      return elem.textContent;
+    });
+
+    is(result, "Hello there.", "Got correct element text from window proxy");
+
+    result = await SpecialPowers.spawn(SpecialPowers.getPrivilegedProps(frame, "browsingContext"),
+                                       ["#span"], selector => {
+      let elem = content.document.querySelector(selector);
+      return elem.textContent;
+    });
+
+    is(result, "Hello there.", "Got correct element text from browsing context");
   });
 </script>
 </body>

testing/specialpowers/content/SpecialPowersAPI.jsm

@@ -1448,18 +1448,19 @@ class SpecialPowersAPI extends JSWindowActorChild {
    * passed will be copied via structured clone, as will its return
    * value.
    *
-   * @param {FrameLoaderOwner} frame
-   *        The frame in which to run the task. This may be any element
-   *        which implements the FrameLoaderOwner nterface, including
-   *        HTML <iframe> elements and XUL <browser> elements.
+   * @param {BrowsingContext or FrameLoaderOwner or WindowProxy} target
+   *        The target in which to run the task. This may be any element
+   *        which implements the FrameLoaderOwner interface (including
+   *        HTML <iframe> elements and XUL <browser> elements) or a
+   *        WindowProxy (either in-process or remote).
    * @param {Array<any>} args
    *        An array of arguments to pass to the task. All arguments
    *        must be structured clone compatible, and will be cloned
    *        before being passed to the task.
    * @param {function} task
-   *        The function to run in the context of the frame. The
+   *        The function to run in the context of the target. The
    *        function will be stringified and re-evaluated in the context
-   *        of the frame's content window. It may return any structured
+   *        of the target's content window. It may return any structured
    *        clone compatible value, or a Promise which resolves to the
    *        same, which will be returned to the caller.
    *
@@ -1470,10 +1471,19 @@ class SpecialPowersAPI extends JSWindowActorChild {
    *        in the cases where the task throws an error, though that may
    *        change in the future.
    */
-  spawn(frame, args, task) {
+  spawn(target, args, task) {
+    let browsingContext;
+    if (BrowsingContext.isInstance(target)) {
+      browsingContext = target;
+    } else if (Element.isInstance(target)) {
+      browsingContext = target.browsingContext;
+    } else {
+      browsingContext = BrowsingContext.getFromWindow(target);
+    }
+
     let {caller} = Components.stack;
     return this.sendQuery("Spawn", {
-      browsingContext: frame.browsingContext,
+      browsingContext,
       args,
       task: String(task),
       caller: {