Bug 1575237 - allow access to all remote child targets' inspector fronts from the root target r=pbro,rcaliman

inspector front; r=!ochameau,!pbro"

Differential Revision: https://phabricator.services.mozilla.com/D43432

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

devtools/shared/fronts/inspector.js

@@ -30,6 +30,7 @@ const TELEMETRY_EYEDROPPER_OPENED_MENU =
 const SHOW_ALL_ANONYMOUS_CONTENT_PREF =
   "devtools.inspector.showAllAnonymousContent";
 const SHOW_UA_SHADOW_ROOTS_PREF = "devtools.inspector.showUserAgentShadowRoots";
+const FISSION_ENABLED = "devtools.browsertoolbox.fission";
 
 const telemetry = new Telemetry();
 
@@ -459,6 +460,9 @@ class WalkerFront extends FrontClassWithSpec(walkerSpec) {
     // Finally retrieve the NodeFront of the remote frame's document
     const documentNode = await walker.getRootNode();
 
+    // Force reparenting through the remote frame boundary.
+    documentNode.reparent(node);
+
     // And return the same kind of response `walker.children` returns
     return {
       nodes: [documentNode],
@@ -564,6 +568,25 @@ class InspectorFront extends FrontClassWithSpec(inspectorSpec) {
       telemetry.getHistogramById(TELEMETRY_EYEDROPPER_OPENED).add(true);
     }
   }
+
+  async getChildInspectors() {
+    const fissionEnabled = Services.prefs.getBoolPref(FISSION_ENABLED);
+    const childInspectors = [];
+    const target = this.targetFront;
+    // this line can be removed when we are ready for fission frames
+    if (fissionEnabled && target.chrome && !target.isAddon) {
+      const { frames } = await target.listRemoteFrames();
+      // attempt to get targets and filter by targets that could connect
+      for (const descriptor of frames) {
+        const remoteTarget = await descriptor.getTarget();
+        if (remoteTarget) {
+          const remoteInspectorFront = await remoteTarget.getFront("inspector");
+          childInspectors.push(remoteInspectorFront);
+        }
+      }
+    }
+    return childInspectors;
+  }
 }
 
 exports.InspectorFront = InspectorFront;