From 9c6f26611e91707727cb3577cc39b90e7104c7a5 Mon Sep 17 00:00:00 2001
From: Steven Orvell <sorvell@google.com>
Date: Thu, 11 Jul 2019 18:01:32 -0700
Subject: [PATCH] Simplify logic for disable-upgrade

---
 lib/legacy/class.js | 57 ++++++++++++++++++++++++---------------------
 1 file changed, 30 insertions(+), 27 deletions(-)

diff --git a/lib/legacy/class.js b/lib/legacy/class.js
index 5e7062c764..9bfd066bf1 100644
--- a/lib/legacy/class.js
+++ b/lib/legacy/class.js
@@ -238,6 +238,24 @@ function GenerateClassFromInfo(info, Base, behaviors) {
       return observedAttributesGetter.call(this).concat(DISABLED_ATTR);
     }
 
+    // Prevent element from initializing properties when it's upgrade disabled.
+    /** @override */
+    _initializeProperties() {
+      if (!this.hasAttribute(DISABLED_ATTR)) {
+        super._initializeProperties();
+      } else {
+        this.__isUpgradeDisabled = true;
+      }
+    }
+
+    // Prevent element from enabling properties when it's upgrade disabled.
+    /** @override */
+    _enableProperties() {
+      if (!this.__isUpgradeDisabled) {
+        super._enableProperties();
+      }
+    }
+
     /**
      * @override
      * @param {string} name Attribute name.
@@ -248,8 +266,14 @@ function GenerateClassFromInfo(info, Base, behaviors) {
      */
     attributeChangedCallback(name, old, value, namespace) {
       if (name == DISABLED_ATTR) {
-        if (!this.__dataEnabled && value == null && this.isConnected) {
-          super.connectedCallback();
+        // When disable-upgrade is removed, intialize properties and
+        // provoke connectedCallback if the element is already connected.
+        if (!this.__dataEnabled && value == null) {
+          super._initializeProperties();
+          this.__isUpgradeDisabled = false;
+          if (this.isConnected) {
+            super.connectedCallback();
+          }
         }
       } else {
         super.attributeChangedCallback(
@@ -257,39 +281,18 @@ function GenerateClassFromInfo(info, Base, behaviors) {
       }
     }
 
-
-    // prevent user code in connected from running
+    // Prevent element from connecting when it's upgrade disabled.
     /** @override */
     connectedCallback() {
-      if (this.__dataEnabled || !this.hasAttribute(DISABLED_ATTR)) {
+      if (!this.__isUpgradeDisabled) {
         super.connectedCallback();
       }
     }
 
-    _initializeProperties() {
-      if (!this.hasAttribute(DISABLED_ATTR)) {
-        super._initializeProperties();
-      } else {
-        this.__wasDisabled = true;
-      }
-    }
-
-    // prevent element from turning on properties
-    /** @override */
-    _enableProperties() {
-      if (this.__wasDisabled) {
-        this.__wasDisabled = false;
-        super._initializeProperties();
-      }
-      if (!this.hasAttribute(DISABLED_ATTR)) {
-        super._enableProperties();
-      }
-    }
-
-    // only go if "enabled"
+    // Prevent element from disconnecting when it's upgrade disabled.
     /** @override */
     disconnectedCallback() {
-      if (this.__dataEnabled) {
+      if (!this.__isUpgradeDisabled) {
         super.disconnectedCallback();
       }
     }