2 files changed, 125 insertions, 0 deletions
diff --git a/browser/extensions/webcompat/experiment-apis/aboutConfigPrefs.js b/browser/extensions/webcompat/experiment-apis/aboutConfigPrefs.js
new file mode 100644
index 0000000000..21ad297dc1
--- /dev/null
+++ b/browser/extensions/webcompat/experiment-apis/aboutConfigPrefs.js
@@ -0,0 +1,53 @@
+/* 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";
+
+/* global ExtensionAPI, ExtensionCommon, Services, XPCOMUtils */
+
+this.aboutConfigPrefs = class extends ExtensionAPI {
+  getAPI(context) {
+    const EventManager = ExtensionCommon.EventManager;
+    const extensionIDBase = context.extension.id.split("@")[0];
+    const extensionPrefNameBase = `extensions.${extensionIDBase}.`;
+
+    return {
+      aboutConfigPrefs: {
+        onPrefChange: new EventManager({
+          context,
+          name: "aboutConfigPrefs.onUAOverridesPrefChange",
+          register: (fire, name) => {
+            const prefName = `${extensionPrefNameBase}${name}`;
+            const callback = () => {
+              fire.async(name).catch(() => {}); // ignore Message Manager disconnects
+            };
+            Services.prefs.addObserver(prefName, callback);
+            return () => {
+              Services.prefs.removeObserver(prefName, callback);
+            };
+          },
+        }).api(),
+        async getBranch(branchName) {
+          const branch = `${extensionPrefNameBase}${branchName}.`;
+          return Services.prefs.getChildList(branch).map(pref => {
+            const name = pref.replace(branch, "");
+            return { name, value: Services.prefs.getBoolPref(pref) };
+          });
+        },
+        async getPref(name) {
+          try {
+            return Services.prefs.getBoolPref(
+              `${extensionPrefNameBase}${name}`
+            );
+          } catch (_) {
+            return undefined;
+          }
+        },
+        async setPref(name, value) {
+          Services.prefs.setBoolPref(`${extensionPrefNameBase}${name}`, value);
+        },
+      },
+    };
+  }
+};
diff --git a/browser/extensions/webcompat/experiment-apis/aboutConfigPrefs.json b/browser/extensions/webcompat/experiment-apis/aboutConfigPrefs.json
new file mode 100644
index 0000000000..44284f199c
--- /dev/null
+++ b/browser/extensions/webcompat/experiment-apis/aboutConfigPrefs.json
@@ -0,0 +1,72 @@
+[
+  {
+    "namespace": "aboutConfigPrefs",
+    "description": "experimental API extension to allow access to about:config preferences",
+    "events": [
+      {
+        "name": "onPrefChange",
+        "type": "function",
+        "parameters": [
+          {
+            "name": "name",
+            "type": "string",
+            "description": "The preference which changed"
+          }
+        ],
+        "extraParameters": [
+          {
+            "name": "name",
+            "type": "string",
+            "description": "The preference to monitor"
+          }
+        ]
+      }
+    ],
+    "functions": [
+      {
+        "name": "getBranch",
+        "type": "function",
+        "description": "Get all child prefs for a branch",
+        "parameters": [
+          {
+            "name": "branchName",
+            "type": "string",
+            "description": "The branch name"
+          }
+        ],
+        "async": true
+      },
+      {
+        "name": "getPref",
+        "type": "function",
+        "description": "Get a preference's value",
+        "parameters": [
+          {
+            "name": "name",
+            "type": "string",
+            "description": "The preference name"
+          }
+        ],
+        "async": true
+      },
+      {
+        "name": "setPref",
+        "type": "function",
+        "description": "Set a preference's value",
+        "parameters": [
+          {
+            "name": "name",
+            "type": "string",
+            "description": "The preference name"
+          },
+          {
+            "name": "value",
+            "type": "boolean",
+            "description": "The new value"
+          }
+        ],
+        "async": true
+      }
+    ]
+  }
+]