Bug 1550090 - Fix theme active check. r=dao

Differential Revision: https://phabricator.services.mozilla.com/D30396

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

toolkit/components/extensions/parent/ext-theme.js

@@ -45,20 +45,11 @@ class Theme {
     if (startupData && startupData.lwtData) {
       Object.assign(this, startupData);
     } else {
-      // TODO(ntim): clean this in bug 1550090
       this.lwtStyles = {};
-      this.lwtDarkStyles = null;
-      if (darkDetails) {
-        this.lwtDarkStyles = {};
-      }
+      this.lwtDarkStyles = {};
 
       if (experiment) {
         if (extension.experimentsAllowed) {
-          this.lwtStyles.experimental = {
-            colors: {},
-            images: {},
-            properties: {},
-          };
           const {baseURI} = this.extension;
           if (experiment.stylesheet) {
             experiment.stylesheet = baseURI.resolve(experiment.stylesheet);
@@ -91,6 +82,8 @@ class Theme {
       this.lwtData = {
         theme: this.lwtStyles,
         darkTheme: this.lwtDarkStyles,
+        id: this.extension.id,
+        version: this.extension.version,
       };
 
       if (this.experiment) {
@@ -126,6 +119,14 @@ class Theme {
    * @param {Object} styles Styles object in which to store the colors.
    */
   loadDetails(details, styles) {
+    if (this.experiment) {
+      styles.experimental = {
+        colors: {},
+        images: {},
+        properties: {},
+      };
+    }
+
     if (details.colors) {
       this.loadColors(details.colors, styles);
     }
@@ -137,8 +138,6 @@ class Theme {
     if (details.properties) {
       this.loadProperties(details.properties, styles);
     }
-
-    this.loadMetadata(this.extension, styles);
   }
 
   /**
@@ -337,21 +336,10 @@ class Theme {
     }
   }
 
-  /**
-   * Helper method for loading extension metadata required by downstream
-   * consumers.
-   *
-   * @param {Object} extension Extension object.
-   * @param {Object} styles Styles object in which to store the colors.
-   */
-  loadMetadata(extension, styles) {
-    styles.id = extension.id;
-    styles.version = extension.version;
-  }
-
   static unload(windowId) {
     let lwtData = {
-      theme: null,
+      theme: {},
+      darkTheme: {},
     };
 
     if (windowId) {

toolkit/modules/LightweightThemeConsumer.jsm

@@ -189,12 +189,9 @@ LightweightThemeConsumer.prototype = {
     this._lastData = themeData;
 
     let theme = themeData.theme;
-    if (themeData.darkTheme && this.darkMode) {
+    if (Object.keys(themeData.darkTheme).length && this.darkMode) {
       theme = themeData.darkTheme;
     }
-    if (!theme) {
-      theme = { id: DEFAULT_THEME_ID };
-    }
 
     let active = this._active = Object.keys(theme).length;
 
@@ -206,8 +203,6 @@ LightweightThemeConsumer.prototype = {
       root.removeAttribute("lwtheme-image");
     }
 
-    this._setExperiment(active, themeData.experiment, theme.experimental);
-
     if (theme.headerImage) {
       this._doc.mozSetImageElement("lwt-header-image", theme.headerImage);
       root.style.setProperty("--lwt-header-image", "-moz-element(#lwt-header-image)");
@@ -218,14 +213,15 @@ LightweightThemeConsumer.prototype = {
 
     _setImage(root, active, "--lwt-additional-images", theme.additionalBackgrounds);
     _setProperties(root, active, theme);
+    this._setExperiment(active, themeData.experiment, theme.experimental);
 
-    if (theme.id != DEFAULT_THEME_ID || this.darkMode) {
+    if (active) {
       root.setAttribute("lwtheme", "true");
     } else {
       root.removeAttribute("lwtheme");
       root.removeAttribute("lwthemetextcolor");
     }
-    if (theme.id == DEFAULT_THEME_ID && this.darkMode) {
+    if (themeData.id == DEFAULT_THEME_ID && this.darkMode) {
       root.setAttribute("lwt-default-theme-in-dark-mode", "true");
     } else {
       root.removeAttribute("lwt-default-theme-in-dark-mode");