Bug 1539265 - Add a few optimisations for ::marker pseudos. r=jdescottes

Where there is existing for ::before and ::after.

Differential Revision: https://phabricator.services.mozilla.com/D25107

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

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

@@ -12,6 +12,7 @@ const Services = require("Services");
 const {
   isAfterPseudoElement,
   isBeforePseudoElement,
+  isMarkerPseudoElement,
   isNativeAnonymous,
 } = require("devtools/shared/layout/utils");
 const Debugger = require("Debugger");
@@ -389,7 +390,7 @@ class JQueryEventCollector extends MainEventCollector {
 
     // If jQuery is not on the page, if this is an anonymous node or a pseudo
     // element we need to return early.
-    if (!jQuery || isNativeAnonymous(node) ||
+    if (!jQuery || isNativeAnonymous(node) || isMarkerPseudoElement(node) ||
         isBeforePseudoElement(node) || isAfterPseudoElement(node)) {
       if (checkOnly) {
         return false;

devtools/server/actors/inspector/node.js

@@ -188,7 +188,9 @@ const NodeActor = protocol.ActorClassWithSpec(nodeSpec, {
   get numChildren() {
     // For pseudo elements, childNodes.length returns 1, but the walker
     // will return 0.
-    if (isBeforePseudoElement(this.rawNode) || isAfterPseudoElement(this.rawNode)) {
+    if (isMarkerPseudoElement(this.rawNode) ||
+      isBeforePseudoElement(this.rawNode) || isAfterPseudoElement(this.rawNode)
+    ) {
       return 0;
     }
 

devtools/server/actors/inspector/walker.js

@@ -17,6 +17,7 @@ loader.lazyRequireGetter(this, "isAfterPseudoElement", "devtools/shared/layout/u
 loader.lazyRequireGetter(this, "isAnonymous", "devtools/shared/layout/utils", true);
 loader.lazyRequireGetter(this, "isBeforePseudoElement", "devtools/shared/layout/utils", true);
 loader.lazyRequireGetter(this, "isDirectShadowHostChild", "devtools/shared/layout/utils", true);
+loader.lazyRequireGetter(this, "isMarkerPseudoElement", "devtools/shared/layout/utils", true);
 loader.lazyRequireGetter(this, "isNativeAnonymous", "devtools/shared/layout/utils", true);
 loader.lazyRequireGetter(this, "isShadowHost", "devtools/shared/layout/utils", true);
 loader.lazyRequireGetter(this, "isShadowRoot", "devtools/shared/layout/utils", true);
@@ -536,7 +537,8 @@ var WalkerActor = protocol.ActorClassWithSpec(walkerSpec, {
    */
   inlineTextChild: function({ rawNode }) {
     // Quick checks to prevent creating a new walker if possible.
-    if (isBeforePseudoElement(rawNode) ||
+    if (isMarkerPseudoElement(rawNode) ||
+        isBeforePseudoElement(rawNode) ||
         isAfterPseudoElement(rawNode) ||
         isShadowHost(rawNode) ||
         rawNode.nodeType != Node.ELEMENT_NODE ||

devtools/shared/layout/utils.js

@@ -638,6 +638,7 @@ exports.isShadowHost = isShadowHost;
 function isDirectShadowHostChild(node) {
   // Pseudo elements and native anonymous elements are always part of the anonymous tree.
   if (
+    isMarkerPseudoElement(node) ||
     isBeforePseudoElement(node) ||
     isAfterPseudoElement(node) ||
     isNativeAnonymous(node)) {