Bug 1757744 - [devtools] Show custom toolbox title for XPCShell debugging r=nchevobbe

Note that XPCShell debugging is usually done via an about:devtools-toolbox tab, so most of the time there will be no title like this.
But we could enable BrowserToolbox xpcshell debugging via https://bugzilla.mozilla.org/show_bug.cgi?id=1620942 and in the meantime this will make it easier to spot configuration issues.

Differential Revision: https://phabricator.services.mozilla.com/D140063

devtools/client/framework/toolbox.js

@@ -3235,7 +3235,11 @@ Toolbox.prototype = {
       this.isBrowserToolbox &&
       Services.prefs.getBoolPref("devtools.browsertoolbox.fission", false);
 
-    if (isMultiProcessBrowserToolbox) {
+    if (this.target.isXpcShellTarget) {
+      // This will only be displayed for local development and can remain
+      // hardcoded in english.
+      title = "XPCShell Toolbox";
+    } else if (isMultiProcessBrowserToolbox) {
       title = L10N.getStr("toolbox.multiProcessBrowserToolboxTitle");
     } else if (this.target.name && this.target.name != this.target.url) {
       const url = this.target.isWebExtension

devtools/client/fronts/targets/content-process.js

@@ -30,6 +30,7 @@ class ContentProcessTargetFront extends TargetMixin(
     this.targetForm = json;
 
     this.remoteType = json.remoteType;
+    this.isXpcShellTarget = json.isXpcShellTarget;
   }
 
   get name() {

devtools/server/actors/targets/content-process.js

@@ -152,10 +152,11 @@ const ContentProcessTargetActor = TargetActorMixin(
       return {
         actor: this.actorID,
         consoleActor: this._consoleActor.actorID,
-        threadActor: this.threadActor.actorID,
+        isXpcShellTarget: this.isXpcShellTarget,
         memoryActor: this.memoryActor.actorID,
         processID: Services.appinfo.processID,
         remoteType: Services.appinfo.remoteType,
+        threadActor: this.threadActor.actorID,
 
         traits: {
           networkMonitor: false,