Bug 1492265 - Remove xpcshell specifics from BrowsingContextTargetActor and ParentProcessTargetActor. r=jdescottes

Now that xpcshell no longer uses ParentProcessTargetActor, we can remove comments about it using it.
We can also remove a couple of null checks against docShell that were specific to this usecase.

MozReview-Commit-ID: 67sugv4bZC3

Depends on D7416

Differential Revision: https://phabricator.services.mozilla.com/D7726

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

devtools/server/actors/targets/browsing-context.js

@@ -336,11 +336,7 @@ const browsingContextTargetPrototype = {
    * Getter for the browsing context's current DOM window.
    */
   get window() {
-    // On xpcshell, there is no document
-    if (this.docShell) {
-      return this.docShell.domWindow;
-    }
-    return null;
+    return this.docShell.domWindow;
   },
 
   get outerWindowID() {
@@ -355,11 +351,10 @@ const browsingContextTargetPrototype = {
    * browsing context's current DOM window.
    */
   get webextensionsContentScriptGlobals() {
-    // Ignore xpcshell runtime which spawns target actors without a window
-    // and only retrieve the content scripts globals if the ExtensionContent JSM module
+    // Only retrieve the content scripts globals if the ExtensionContent JSM module
     // has been already loaded (which is true if the WebExtensions internals have already
     // been loaded in the same content process).
-    if (this.window && Cu.isModuleLoaded(EXTENSION_CONTENT_JSM)) {
+    if (Cu.isModuleLoaded(EXTENSION_CONTENT_JSM)) {
       return ExtensionContent.getContentScriptGlobals(this.window);
     }
 
@@ -460,17 +455,15 @@ const browsingContextTargetPrototype = {
     const response = {
       actor: this.actorID,
       traits: {
-        // FF64+ exposes a new trait to help identify ParentProcessTargetActor used for
-        // xpcshell that isn't attached to any valid browsing context and so shouldn't
-        // be considered as a browsing context-inherited target on the client side.
-        isBrowsingContext: !!this.docShell,
+        // FF64+ exposes a new trait to help identify BrowsingContextActor's inherited
+        // actorss from the client side.
+        isBrowsingContext: true,
       },
     };
 
-    // We may try to access window while the document is closing, then
-    // accessing window throws. Also on xpcshell we are using this actor even if
-    // there is no valid document.
-    if (this.docShell && !this.docShell.isBeingDestroyed()) {
+    // We may try to access window while the document is closing, then accessing window
+    // throws.
+    if (!this.docShell.isBeingDestroyed()) {
       response.title = this.title;
       response.url = this.url;
       response.outerWindowID = this.outerWindowID;
@@ -575,17 +568,14 @@ const browsingContextTargetPrototype = {
     // Create a pool for context-lifetime actors.
     this._createThreadActor();
 
-    // on xpcshell, there is no document
-    if (this.window) {
-      this._progressListener = new DebuggerProgressListener(this);
+    this._progressListener = new DebuggerProgressListener(this);
 
-      // Save references to the original document we attached to
-      this._originalWindow = this.window;
+    // Save references to the original document we attached to
+    this._originalWindow = this.window;
 
-      // Ensure replying to attach() request first
-      // before notifying about new docshells.
-      DevToolsUtils.executeSoon(() => this._watchDocshells());
-    }
+    // Ensure replying to attach() request first
+    // before notifying about new docshells.
+    DevToolsUtils.executeSoon(() => this._watchDocshells());
 
     this._attached = true;
   },

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

@@ -43,8 +43,11 @@ const parentProcessTargetPrototype = extend({}, browsingContextTargetPrototype);
  *
  * @param connection DebuggerServerConnection
  *        The connection to the client.
+ * @param window Window object (optional)
+ *        If the upper class already knows against which window the actor should attach,
+ *        it is passed as a constructor argument here.
  */
-parentProcessTargetPrototype.initialize = function(connection) {
+parentProcessTargetPrototype.initialize = function(connection, window) {
   BrowsingContextTargetActor.prototype.initialize.call(this, connection);
 
   // This creates a Debugger instance for chrome debugging all globals.
@@ -57,7 +60,9 @@ parentProcessTargetPrototype.initialize = function(connection) {
   this.listenForNewDocShells = true;
 
   // Defines the default docshell selected for the target actor
-  let window = Services.wm.getMostRecentWindow(DebuggerServer.chromeWindowType);
+  if (!window) {
+    window = Services.wm.getMostRecentWindow(DebuggerServer.chromeWindowType);
+  }
 
   // Default to any available top level window if there is no expected window
   // (for example when we open firefox with -webide argument)
@@ -68,17 +73,11 @@ parentProcessTargetPrototype.initialize = function(connection) {
   // We really want _some_ window at least, so fallback to the hidden window if
   // there's nothing else (such as during early startup).
   if (!window) {
-    try {
-      window = Services.appShell.hiddenDOMWindow;
-    } catch (e) {
-      // On XPCShell, the above line will throw.
-    }
+    window = Services.appShell.hiddenDOMWindow;
   }
 
-  // On XPCShell, there is no window/docshell
-  const docShell = window ? window.docShell : null;
   Object.defineProperty(this, "docShell", {
-    value: docShell,
+    value: window.docShell,
     configurable: true
   });
 };

devtools/server/actors/targets/webextension.js

@@ -75,10 +75,19 @@ const webExtensionTargetPrototype = extend({}, parentProcessTargetPrototype);
  *        the addonId of the target WebExtension.
  */
 webExtensionTargetPrototype.initialize = function(conn, chromeGlobal, prefix, addonId) {
-  parentProcessTargetPrototype.initialize.call(this, conn);
+  this.id = addonId;
+
+  // Try to discovery an existent extension page to attach (which will provide the initial
+  // URL shown in the window tittle when the addon debugger is opened).
+  let extensionWindow = this._searchForExtensionWindow();
+  if (!extensionWindow) {
+    this._createFallbackWindow();
+    extensionWindow = this.fallbackWindow;
+  }
+
+  parentProcessTargetPrototype.initialize.call(this, conn, extensionWindow);
   this._chromeGlobal = chromeGlobal;
   this._prefix = prefix;
-  this.id = addonId;
 
   // Redefine the messageManager getter to return the chromeGlobal
   // as the messageManager for this actor (which is the browser XUL
@@ -115,14 +124,6 @@ webExtensionTargetPrototype.initialize = function(conn, chromeGlobal, prefix, ad
     },
     shouldAddNewGlobalAsDebuggee: this._shouldAddNewGlobalAsDebuggee.bind(this),
   });
-
-  // Try to discovery an existent extension page to attach (which will provide the initial
-  // URL shown in the window tittle when the addon debugger is opened).
-  const extensionWindow = this._searchForExtensionWindow();
-
-  if (extensionWindow) {
-    this._setWindow(extensionWindow);
-  }
 };
 
 // NOTE: This is needed to catch in the webextension webconsole all the