Bug 1680218 - [devtools] Remove supportsNodePicker trait. r=rcaliman.

The trait was introduced in Firefox 80, so it's
safe to remove it now.

Differential Revision: https://phabricator.services.mozilla.com/D98487

devtools/client/fronts/walker.js

@@ -583,16 +583,8 @@ class WalkerFront extends FrontClassWithSpec(walkerSpec) {
     if (this._isPicking) {
       return Promise.resolve();
     }
+
     this._isPicking = true;
-
-    // @backward-compat { version 80 } On older server, walker.pick doesn't exist.
-    if (!this.traits.supportsNodePicker) {
-      // parent is InspectorFront
-      return doFocus
-        ? this.parentFront.highlighter.pickAndFocus()
-        : this.parentFront.highlighter.pick();
-    }
-
     return super.pick(doFocus);
   }
 
@@ -603,14 +595,8 @@ class WalkerFront extends FrontClassWithSpec(walkerSpec) {
     if (!this._isPicking) {
       return Promise.resolve();
     }
+
     this._isPicking = false;
-
-    // @backward-compat { version 80 } On older server, walker.cancelPick doesn't exist.
-    if (!this.traits.supportsNodePicker) {
-      // parent is InspectorFront
-      return this.parentFront.highlighter.cancelPick();
-    }
-
     return super.cancelPick();
   }
 }

devtools/server/actors/inspector/walker.js

@@ -321,8 +321,6 @@ var WalkerActor = protocol.ActorClassWithSpec(walkerSpec, {
       actor: this.actorID,
       root: this.rootNode.form(),
       traits: {
-        // @backward-compat { version 80 } Walker implements node picker
-        supportsNodePicker: true,
         // @backward-compat { version 83 } Walker implements overflow debugging support
         supportsOverflowDebugging2: true,
       },