Portals: Do not create a RemoteFrame for a portal when a portal if

inserted into a disconnected node.

Bug: 1029508
Change-Id: I8d90a488198b0772baa2bd41a16c6a330fc792fa
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1943310Reviewed-by: Jeremy Roman <jbroman@chromium.org>
Commit-Queue: Lucas Gadani <lfg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#720283}

third_party/blink/renderer/core/html/portal/html_portal_element.cc

@@ -300,6 +300,13 @@ HTMLPortalElement::InsertionNotificationRequest HTMLPortalElement::InsertedInto(
       break;
   };
 
+  // When adopting a predecessor, it is possible to insert a portal that's
+  // eligible to have a guest contents to a node that's not connected. In this
+  // case, do not create the portal frame yet.
+  if (!node.isConnected()) {
+    return result;
+  }
+
   if (portal_) {
     // The interface is already bound if the HTMLPortalElement is adopting the
     // predecessor.

third_party/blink/web_tests/external/wpt/portals/portals-adopt-predecessor.html

@@ -62,4 +62,14 @@
     });
     window.open(`resources/portals-adopt-predecessor.html?test=${test}`);
   }, "Tests that the adopted predecessor is destroyed if it isn't inserted");
+
+  async_test(t => {
+    var test = "adopt-to-disconnected-node";
+    var bc = new BroadcastChannel(`test-${test}`);
+    bc.onmessage = t.step_func_done(function(e) {
+      assert_equals(e.data, "passed");
+      bc.close();
+    });
+    window.open(`resources/portals-adopt-predecessor.html?test=${test}`);
+  }, "Tests that an adopted portal can be inserted into a disconnected node.");
 </script>

third_party/blink/web_tests/external/wpt/portals/resources/portals-adopt-predecessor-portal.html

@@ -64,5 +64,14 @@
         });
       });
     }
+    if (test == "adopt-to-disconnected-node") {
+      var portal = e.adoptPredecessor();
+      document.body.appendChild(portal);
+      var node = document.createElement("div");
+      node.appendChild(portal);
+      var bc_test = new BroadcastChannel(`test-${test}`);
+      bc_test.postMessage("passed");
+      bc_test.close();
+    }
   }
 </script>