Enable permanent loading of webextensions from sources in about:debugging of latest Firefox Nightly

0001.patch

diff --git a/devtools/modules/devtools/client/aboutdebugging/components/addons/controls.js b/devtools/modules/devtools/client/aboutdebugging/components/addons/controls.js
--- a/devtools/modules/devtools/client/aboutdebugging/components/addons/controls.js
+++ b/devtools/modules/devtools/client/aboutdebugging/components/addons/controls.js
@@ -9,6 +9,8 @@
 
 loader.lazyImporter(this, "AddonManager",
   "resource://gre/modules/AddonManager.jsm");
+loader.lazyImporter(this, "AppConstants",
+  "resource://gre/modules/AppConstants.jsm");
 
 const { Cc, Ci } = require("chrome");
 const { createFactory, createClass, DOM: dom, PropTypes } =
@@ -65,8 +67,39 @@ module.exports = createClass({
       });
   },
 
+  loadAddonFromSources() {
+    this.setState({ installError: null });
+    let fp = Cc["@mozilla.org/filepicker;1"].createInstance(Ci.nsIFilePicker);
+    fp.init(window,
+      Strings.GetStringFromName("selectAddonFromSources"),
+      Ci.nsIFilePicker.modeGetFolder);
+    let res = fp.show();
+    if (res == Ci.nsIFilePicker.returnCancel || !fp.file ||
+        !fp.file.isDirectory()) {
+      return;
+    }
+
+    AddonManager.installAddonFromSources(fp.file)
+      .catch(e => {
+        console.error(e);
+        this.setState({ installError: e.message });
+      });
+  },
+
   render() {
     let { debugDisabled } = this.props;
+    let signRequired = Services.prefs.getBoolPref(
+      "xpinstall.signatures.required");
+    let loadFromSourcesTooltip;
+    if (signRequired) {
+      if (AppConstants.RELEASE_OR_BETA) {
+        loadFromSourcesTooltip = Strings.GetStringFromName(
+          "loadPermanentlyAddon.releaseTooltip");
+      } else {
+        loadFromSourcesTooltip = Strings.GetStringFromName(
+          "loadPermanentlyAddon.signature");
+      }
+    }
 
     return dom.div({ className: "addons-top" },
       dom.div({ className: "addons-controls" },
@@ -90,7 +123,13 @@ module.exports = createClass({
         dom.button({
           id: "load-addon-from-file",
           onClick: this.loadAddonFromFile,
-        }, Strings.GetStringFromName("loadTemporaryAddon"))
+        }, Strings.GetStringFromName("loadTemporaryAddon")),
+        dom.button({
+          id: "load-addon-from-sources",
+          onClick: this.loadAddonFromSources,
+          disabled: signRequired,
+          title: loadFromSourcesTooltip
+        }, Strings.GetStringFromName("loadPermanentlyAddon"))
       ),
       AddonsInstallError({ error: this.state.installError }));
   }
diff --git a/en-US/locale/en-US/devtools/client/aboutdebugging.properties b/en-US/locale/en-US/devtools/client/aboutdebugging.properties
--- a/en-US/locale/en-US/devtools/client/aboutdebugging.properties
+++ b/en-US/locale/en-US/devtools/client/aboutdebugging.properties
@@ -45,6 +45,23 @@ moreInfo = more info
 # load additional add-ons.
 loadTemporaryAddon = Load Temporary Add-on
 
+# LOCALIZATION NOTE (loadPermanentlyAddon):
+# This string is displayed as a label of a button that allows the user to
+# load additional add-ons.
+loadPermanentlyAddon = Load Unpackaged Add-on Permanently
+
+# LOCALIZATION NOTE (loadPermanentlyAddon.releaseTooltip):
+# This string is displayed as a tooltip of the 'Load Unpackaged Add-on
+# Permanently' button when running on release build where this button
+# is always disabled.
+loadPermanentlyAddon.releaseTooltip = This features only work on non-release build like Developer Edition or Nightly
+
+# LOCALIZATION NOTE (loadPermanentlyAddon.signature):
+# This string is displayed as a tooltip of the 'Load Unpackaged Add-on
+# Permanently' button when the signature preference is turned on and the button
+# is disabled.
+loadPermanentlyAddon.signature = 'xpinstall.signatures.required' preference needs to be toggled to false
+
 # LOCALIZATION NOTE (extensions):
 # This string is displayed as a header above the list of loaded add-ons.
 extensions = Extensions
@@ -54,6 +71,11 @@ extensions = Extensions
 # the user clicks the 'Load Temporary Add-on' button
 selectAddonFromFile2 = Select Manifest File or Package (.xpi)
 
+# LOCALIZATION NOTE (selectAddonFromSources):
+# This string is displayed as the title of the file picker that appears when
+# the user clicks the 'Load Unpacked Add-on Permanently' button
+selectAddonFromSources = Select Add-on directory
+
 # LOCALIZATION NOTE (reload):
 # This string is displayed as a label of the button that reloads a given addon.
 reload = Reload