From 8066e0214a74a3c2a88b16a1f6f291bb66342793 Mon Sep 17 00:00:00 2001
From: Yura Zenevich <yura.zenevich@gmail.com>
Date: Tue, 30 Oct 2018 17:52:24 +0000
Subject: [PATCH] Bug 1498235 - lazy load accessibility highlighter in
 accessibility walker actor. r=gl

MozReview-Commit-ID: 7xFlSocDPVG

Differential Revision: https://phabricator.services.mozilla.com/D9581

--HG--
extra : moz-landing-system : lando
---
 .../server/actors/accessibility/walker.js     | 50 ++++++++++++++-----
 1 file changed, 37 insertions(+), 13 deletions(-)

diff --git a/devtools/server/actors/accessibility/walker.js b/devtools/server/actors/accessibility/walker.js
index 21816d40ee6d..37916e0a413c 100644
--- a/devtools/server/actors/accessibility/walker.js
+++ b/devtools/server/actors/accessibility/walker.js
@@ -8,15 +8,16 @@ const { Cc, Ci } = require("chrome");
 const Services = require("Services");
 const { Actor, ActorClassWithSpec } = require("devtools/shared/protocol");
 const { accessibleWalkerSpec } = require("devtools/shared/specs/accessibility");
-const { isXUL } = require("devtools/server/actors/highlighters/utils/markup");
-const { CustomHighlighterActor, register } =
-  require("devtools/server/actors/highlighters");
 
 loader.lazyRequireGetter(this, "AccessibleActor", "devtools/server/actors/accessibility/accessible", true);
+loader.lazyRequireGetter(this, "CustomHighlighterActor", "devtools/server/actors/highlighters", true);
 loader.lazyRequireGetter(this, "DevToolsUtils", "devtools/shared/DevToolsUtils");
 loader.lazyRequireGetter(this, "events", "devtools/shared/event-emitter");
 loader.lazyRequireGetter(this, "isDefunct", "devtools/server/actors/utils/accessibility", true);
+loader.lazyRequireGetter(this, "isTypeRegistered", "devtools/server/actors/highlighters", true);
 loader.lazyRequireGetter(this, "isWindowIncluded", "devtools/shared/layout/utils", true);
+loader.lazyRequireGetter(this, "isXUL", "devtools/server/actors/highlighters/utils/markup", true);
+loader.lazyRequireGetter(this, "register", "devtools/server/actors/highlighters", true);
 
 const nsIAccessibleEvent = Ci.nsIAccessibleEvent;
 const nsIAccessibleStateChangeEvent = Ci.nsIAccessibleStateChangeEvent;
@@ -92,9 +93,6 @@ const NAME_FROM_SUBTREE_RULE_ROLES = new Set([
 
 const IS_OSX = Services.appinfo.OS === "Darwin";
 
-register("AccessibleHighlighter", "accessible");
-register("XULWindowAccessibleHighlighter", "xul-accessible");
-
 /**
  * Helper function that determines if nsIAccessible object is in stale state. When an
  * object is stale it means its subtree is not up to date.
@@ -130,12 +128,30 @@ const AccessibleWalkerActor = ActorClassWithSpec(accessibleWalkerSpec, {
     this.onHovered = this.onHovered.bind(this);
     this.onKey = this.onKey.bind(this);
     this.onHighlighterEvent = this.onHighlighterEvent.bind(this);
+  },
 
-    this.highlighter = CustomHighlighterActor(this, isXUL(this.rootWin) ?
-      "XULWindowAccessibleHighlighter" : "AccessibleHighlighter");
+  get highlighter() {
+    if (!this._highlighter) {
+      if (isXUL(this.rootWin)) {
+        if (!isTypeRegistered("XULWindowAccessibleHighlighter")) {
+          register("XULWindowAccessibleHighlighter", "xul-accessible");
+        }
 
-    this.manage(this.highlighter);
-    this.highlighter.on("highlighter-event", this.onHighlighterEvent);
+        this._highlighter = CustomHighlighterActor(this,
+                                                   "XULWindowAccessibleHighlighter");
+      } else {
+        if (!isTypeRegistered("AccessibleHighlighter")) {
+          register("AccessibleHighlighter", "accessible");
+        }
+
+        this._highlighter = CustomHighlighterActor(this, "AccessibleHighlighter");
+      }
+
+      this.manage(this._highlighter);
+      this._highlighter.on("highlighter-event", this.onHighlighterEvent);
+    }
+
+    return this._highlighter;
   },
 
   setA11yServiceGetter() {
@@ -188,8 +204,10 @@ const AccessibleWalkerActor = ActorClassWithSpec(accessibleWalkerSpec, {
 
     this.reset();
 
-    this.highlighter.off("highlighter-event", this.onHighlighterEvent);
-    this.highlighter = null;
+    if (this._highlighter) {
+      this._highlighter.off("highlighter-event", this.onHighlighterEvent);
+      this._highlighter = null;
+    }
 
     this.targetActor = null;
     this.refMap = null;
@@ -470,6 +488,10 @@ const AccessibleWalkerActor = ActorClassWithSpec(accessibleWalkerSpec, {
    * side.
    */
   unhighlight() {
+    if (!this._highlighter) {
+      return;
+    }
+
     this.highlighter.hide();
   },
 
@@ -701,7 +723,9 @@ const AccessibleWalkerActor = ActorClassWithSpec(accessibleWalkerSpec, {
    * Cacncel picker pick. Remvoe all content listeners and hide the highlighter.
    */
   cancelPick: function() {
-    this.highlighter.hide();
+    if (this._highlighter) {
+      this.highlighter.hide();
+    }
 
     if (this._isPicking) {
       this._stopPickerListeners();