Bug 1673627 - [devtools] Force showing iframe content instead of inline content for remote frames. r=jdescottes

For some reason we return an inlineTextChild when the iframe is remote, so only with fission turned on.
When the iframe isn't remote, WalkerFront.inlineTextChild returns undefined.

Differential Revision: https://phabricator.services.mozilla.com/D95868

devtools/client/inspector/test/browser.ini

@@ -74,6 +74,7 @@ skip-if = (os == 'win' && processor == 'aarch64') # bug 1533490
 [browser_inspector_destroy-after-navigation.js]
 [browser_inspector_destroy-before-ready.js]
 [browser_inspector_expand-collapse.js]
+[browser_inspector_fission_frame.js]
 [browser_inspector_fission_frame_navigation.js]
 skip-if = fission && (bits == 64 && (os == "win" || os == "linux")) # Bug 1665482
 [browser_inspector_fission_switch_target.js]

devtools/client/inspector/test/browser_inspector_fission_frame.js

@@ -0,0 +1,22 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
+
+/**
+ * bug 1673627 - Test that remote iframes with short inline content,
+ * get their inner remote document displayed instead of the inlineTextChild content.
+ */
+const TEST_URI = `data:text/html,<div id="root"><iframe src="http://example.com/document-builder.sjs?html=<div id=com>com"><br></iframe></div>`;
+
+add_task(async function() {
+  const { inspector } = await openInspectorForURL(TEST_URI);
+  const tree = `
+    id="root"
+      iframe
+        #document
+          html
+            head
+            body
+              id="com"`;
+  await assertMarkupViewAsTree(tree, "#root", inspector);
+});

devtools/server/actors/inspector/walker.js

@@ -29,6 +29,7 @@ loader.lazyRequireGetter(
     "isDirectShadowHostChild",
     "isMarkerPseudoElement",
     "isNativeAnonymous",
+    "isRemoteFrame",
     "isShadowHost",
     "isShadowRoot",
     "isTemplateElement",
@@ -719,7 +720,8 @@ var WalkerActor = protocol.ActorClassWithSpec(walkerSpec, {
       isAfterPseudoElement(rawNode) ||
       isShadowHost(rawNode) ||
       rawNode.nodeType != Node.ELEMENT_NODE ||
-      rawNode.children.length > 0
+      rawNode.children.length > 0 ||
+      isRemoteFrame(rawNode)
     ) {
       return undefined;
     }