Bug 1474163 - Make use of sharedData for content theme data. r=mconley

MozReview-Commit-ID: Etz8huX2YCt

browser/modules/LightweightThemeChildHelper.jsm

@@ -0,0 +1,71 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+ChromeUtils.import("resource://gre/modules/Services.jsm");
+
+var EXPORTED_SYMBOLS = ["LightweightThemeChildHelper"];
+
+/**
+ * LightweightThemeChildHelper forwards theme data to in-content pages.
+ */
+var LightweightThemeChildHelper = {
+  listener: null,
+  whitelist: [],
+
+  /**
+   * Listen to theme updates for the current process
+   * @param {Array} whitelist The pages that can receive theme updates.
+   */
+  listen(whitelist) {
+    if (!this.listener) {
+      // Clone the whitelist to avoid leaking the global the whitelist
+      // originates from.
+      this.whitelist = new Set([...whitelist]);
+      this.listener = ({ changedKeys }) => {
+        if (changedKeys.find(change => change.startsWith("theme/"))) {
+          this._updateProcess(changedKeys);
+        }
+      };
+      Services.cpmm.sharedData.addEventListener("change", this.listener);
+    }
+  },
+
+  /**
+   * Update the theme data for the whole process
+   * @param {Array} changedKeys The sharedData keys that were changed.
+   */
+  _updateProcess(changedKeys) {
+    const windowEnumerator = Services.ww.getWindowEnumerator();
+    while (windowEnumerator.hasMoreElements()) {
+      const window = windowEnumerator.getNext().QueryInterface(Ci.nsIDOMWindow);
+      const tabChildGlobal = window.QueryInterface(Ci.nsIInterfaceRequestor)
+                                   .getInterface(Ci.nsIDocShell)
+                                   .sameTypeRootTreeItem
+                                   .QueryInterface(Ci.nsIInterfaceRequestor)
+                                   .getInterface(Ci.nsIContentFrameMessageManager);
+      const {chromeOuterWindowID, content} = tabChildGlobal;
+      if (changedKeys.includes(`theme/${chromeOuterWindowID}`) &&
+          content && this.whitelist.has(content.document.documentURI)) {
+        this.update(chromeOuterWindowID, content);
+      }
+    }
+  },
+
+  /**
+   * Forward the theme data to the page.
+   * @param {Object} outerWindowID The outerWindowID the parent process window has.
+   * @param {Object} content The receiving global
+   */
+  update(outerWindowID, content) {
+    const event = Cu.cloneInto({
+      detail: {
+        data: Services.cpmm.sharedData.get(`theme/${outerWindowID}`)
+      },
+    }, content);
+    content.dispatchEvent(new content.CustomEvent("LightweightTheme:Set",
+                                                  event));
+  },
+};

browser/modules/LightweightThemeChildListener.jsm

@@ -1,82 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this file,
- * You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-"use strict";
-
-/**
- * LightweightThemeChildListener forwards theme updates from LightweightThemeConsumer to
- * the whitelisted in-content pages
- */
-class LightweightThemeChildListener {
-  constructor() {
-    /**
-     * The pages that will receive theme updates
-     */
-    this.whitelist = new Set([
-      "about:home",
-      "about:newtab",
-      "about:welcome",
-    ]);
-
-    /**
-     * The last theme data received from LightweightThemeConsumer
-     */
-    this._lastData = null;
-  }
-
-  /**
-   * Handles theme updates from the parent process
-   * @param {Object} message from the parent process.
-   */
-  receiveMessage({ name, data, target }) {
-    if (name == "LightweightTheme:Update") {
-      this._lastData = data;
-      this._update(data, target.content);
-    }
-  }
-
-  /**
-   * Handles events from the content scope.
-   * @param {Object} event The received event.
-   */
-  handleEvent(event) {
-    const content = event.originalTarget.defaultView;
-    if (content != content.top) {
-      return;
-    }
-
-    if (event.type == "LightweightTheme:Support") {
-      this._update(this._lastData, content);
-    }
-  }
-
-  /**
-   * Checks if a given global is allowed to receive theme updates
-   * @param {Object} content The global to check against.
-   * @returns {boolean} Whether the global is allowed to receive updates.
-   */
-  _isContentWhitelisted(content) {
-    return this.whitelist.has(content.document.documentURI);
-  }
-
-  /**
-   * Forward the theme data to the page.
-   * @param {Object} data The theme data to forward
-   * @param {Object} content The receiving global
-   */
-  _update(data, content) {
-    if (this._isContentWhitelisted(content)) {
-      const event = Cu.cloneInto({
-        detail: {
-          type: "LightweightTheme:Update",
-          data,
-        },
-      }, content);
-      content.dispatchEvent(new content.CustomEvent("LightweightTheme:Set",
-                                                    event));
-    }
-  }
-}
-
-var EXPORTED_SYMBOLS = ["LightweightThemeChildListener"];

browser/modules/moz.build

@@ -64,7 +64,7 @@ with Files("ExtensionsUI.jsm"):
 with Files("LaterRun.jsm"):
     BUG_COMPONENT = ("Firefox", "Tours")
 
-with Files("LightweightThemeChildListener.jsm"):
+with Files("LightweightThemeChildHelper.jsm"):
     BUG_COMPONENT = ("WebExtensions", "Themes")
 
 with Files("LightWeightThemeWebInstallListener.jsm"):
@@ -153,7 +153,7 @@ EXTRA_JS_MODULES += [
     'FormValidationHandler.jsm',
     'HomePage.jsm',
     'LaterRun.jsm',
-    'LightweightThemeChildListener.jsm',
+    'LightweightThemeChildHelper.jsm',
     'LightWeightThemeWebInstallListener.jsm',
     'NetErrorContent.jsm',
     'OpenInTabsUtils.jsm',