1 files changed, 45 insertions, 0 deletions
diff --git a/toolkit/components/webextensions/ext-c-backgroundPage.js b/toolkit/components/webextensions/ext-c-backgroundPage.js
new file mode 100644
index 000000000..b5074dd9a
--- /dev/null
+++ b/toolkit/components/webextensions/ext-c-backgroundPage.js
@@ -0,0 +1,45 @@
+"use strict";
+
+global.initializeBackgroundPage = (contentWindow) => {
+  // Override the `alert()` method inside background windows;
+  // we alias it to console.log().
+  // See: https://bugzilla.mozilla.org/show_bug.cgi?id=1203394
+  let alertDisplayedWarning = false;
+  let alertOverwrite = text => {
+    if (!alertDisplayedWarning) {
+      require("devtools/client/framework/devtools-browser");
+
+      let hudservice = require("devtools/client/webconsole/hudservice");
+      hudservice.openBrowserConsoleOrFocus();
+
+      contentWindow.console.warn("alert() is not supported in background windows; please use console.log instead.");
+
+      alertDisplayedWarning = true;
+    }
+
+    contentWindow.console.log(text);
+  };
+  Cu.exportFunction(alertOverwrite, contentWindow, {defineAs: "alert"});
+};
+
+extensions.registerSchemaAPI("extension", "addon_child", context => {
+  function getBackgroundPage() {
+    for (let view of context.extension.views) {
+      if (view.viewType == "background" && context.principal.subsumes(view.principal)) {
+        return view.contentWindow;
+      }
+    }
+    return null;
+  }
+  return {
+    extension: {
+      getBackgroundPage,
+    },
+
+    runtime: {
+      getBackgroundPage() {
+        return context.cloneScope.Promise.resolve(getBackgroundPage());
+      },
+    },
+  };
+});