Bug 1576908 - uses fission model for sending purge history messages r=mconley,Gijs

Differential Revision: https://phabricator.services.mozilla.com/D45959

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

toolkit/actors/PurgeSessionHistoryChild.jsm

@@ -6,11 +6,7 @@
 
 var EXPORTED_SYMBOLS = ["PurgeSessionHistoryChild"];
 
-const { ActorChild } = ChromeUtils.import(
-  "resource://gre/modules/ActorChild.jsm"
-);
-
-class PurgeSessionHistoryChild extends ActorChild {
+class PurgeSessionHistoryChild extends JSWindowActorChild {
   receiveMessage(message) {
     if (message.name != "Browser:PurgeSessionHistory") {
       return;
@@ -30,7 +26,7 @@ class PurgeSessionHistoryChild extends ActorChild {
     }
 
     let purge = sessionHistory.count;
-    if (this.content.location.href != "about:blank") {
+    if (this.document.location.href != "about:blank") {
       --purge; // Don't remove the page the user's staring at from shistory
     }
 

toolkit/content/widgets/browser-custom-element.js

@@ -1593,19 +1593,22 @@
 
     purgeSessionHistory() {
       if (this.isRemoteBrowser) {
-        try {
-          this.messageManager.sendAsyncMessage("Browser:PurgeSessionHistory");
-        } catch (ex) {
-          // This can throw if the browser has started to go away.
-          if (ex.result != Cr.NS_ERROR_NOT_INITIALIZED) {
-            throw ex;
-          }
-        }
         this._remoteWebNavigationImpl.canGoBack = false;
         this._remoteWebNavigationImpl.canGoForward = false;
-        return;
       }
-      this.messageManager.sendAsyncMessage("Browser:PurgeSessionHistory");
+      try {
+        this.sendMessageToActor(
+          "Browser:PurgeSessionHistory",
+          {},
+          "PurgeSessionHistory",
+          true
+        );
+      } catch (ex) {
+        // This can throw if the browser has started to go away.
+        if (ex.result != Cr.NS_ERROR_NOT_INITIALIZED) {
+          throw ex;
+        }
+      }
     }
 
     createAboutBlankContentViewer(aPrincipal, aStoragePrincipal) {

toolkit/modules/ActorManagerParent.jsm

@@ -275,6 +275,12 @@ let ACTORS = {
 
     allFrames: true,
   },
+  PurgeSessionHistory: {
+    child: {
+      moduleURI: "resource://gre/actors/PurgeSessionHistoryChild.jsm",
+    },
+    allFrames: true,
+  },
 };
 
 let LEGACY_ACTORS = {
@@ -370,13 +376,6 @@ let LEGACY_ACTORS = {
     },
   },
 
-  PurgeSessionHistory: {
-    child: {
-      module: "resource://gre/actors/PurgeSessionHistoryChild.jsm",
-      messages: ["Browser:PurgeSessionHistory"],
-    },
-  },
-
   SelectionSource: {
     child: {
       module: "resource://gre/actors/SelectionSourceChild.jsm",