diff --git a/toolkit/components/extensions/Extension.jsm b/toolkit/components/extensions/Extension.jsm
index 3985cb0359c0..a38d13c39331 100644
--- a/toolkit/components/extensions/Extension.jsm
+++ b/toolkit/components/extensions/Extension.jsm
@@ -363,16 +363,12 @@ GlobalManager = {
       Schemas.inject(chromeObj, schemaWrapper);
     };
 
-    let id = ExtensionManagement.getAddonIdForWindow(contentWindow);
-
-    // We don't inject privileged APIs into sub-frames of a UI page.
-    const { FULL_PRIVILEGES } = ExtensionManagement.API_LEVELS;
-    if (ExtensionManagement.getAPILevelForWindow(contentWindow, id) !== FULL_PRIVILEGES) {
-      return;
-    }
-
-    // We don't inject privileged APIs if the addonId is null
-    // or doesn't exist.
+    // Find the add-on associated with this document via the
+    // principal's originAttributes. This value is computed by
+    // extensionURIToAddonID, which ensures that we don't inject our
+    // API into webAccessibleResources or remote web pages.
+    let principal = contentWindow.document.nodePrincipal;
+    let id = principal.originAttributes.addonId;
     if (!this.extensionMap.has(id)) {
       return;
     }
@@ -391,6 +387,10 @@ GlobalManager = {
       return;
     }
 
+    // We don't inject into sub-frames of a UI page.
+    if (contentWindow != contentWindow.top) {
+      return;
+    }
     let extension = this.extensionMap.get(id);
     let uri = contentWindow.document.documentURIObject;
     let incognito = PrivateBrowsingUtils.isContentWindowPrivate(contentWindow);
diff --git a/toolkit/components/extensions/ExtensionContent.jsm b/toolkit/components/extensions/ExtensionContent.jsm
index 78a28d515b11..bcc2c958e3a3 100644
--- a/toolkit/components/extensions/ExtensionContent.jsm
+++ b/toolkit/components/extensions/ExtensionContent.jsm
@@ -216,10 +216,7 @@ var ExtensionManager;
 // Scope in which extension content script code can run. It uses
 // Cu.Sandbox to run the code. There is a separate scope for each
 // frame.
-function ExtensionContext(extensionId, contentWindow, contextOptions = {}) {
-  let { isExtensionPage } = contextOptions;
-
-  this.isExtensionPage = isExtensionPage;
+function ExtensionContext(extensionId, contentWindow) {
   this.extension = ExtensionManager.get(extensionId);
   this.extensionId = extensionId;
   this.contentWindow = contentWindow;
@@ -246,27 +243,12 @@ function ExtensionContext(extensionId, contentWindow, contextOptions = {}) {
     prin = [contentPrincipal, extensionPrincipal];
   }
 
-  if (isExtensionPage) {
-    if (ExtensionManagement.getAddonIdForWindow(this.contentWindow) != extensionId) {
-      throw new Error("Invalid target window for this extension context");
-    }
-    // This is an iframe with content script API enabled and its principal should be the
-    // contentWindow itself. (we create a sandbox with the contentWindow as principal and with X-rays disabled
-    // because it enables us to create the APIs object in this sandbox object and then copying it
-    // into the iframe's window, see Bug 1214658 for rationale)
-    this.sandbox = Cu.Sandbox(contentWindow, {
-      sandboxPrototype: contentWindow,
-      wantXrays: false,
-      isWebExtensionContentScript: true,
-    });
-  } else {
-    this.sandbox = Cu.Sandbox(prin, {
-      sandboxPrototype: contentWindow,
-      wantXrays: true,
-      isWebExtensionContentScript: true,
-      wantGlobalProperties: ["XMLHttpRequest"],
-    });
-  }
+  this.sandbox = Cu.Sandbox(prin, {
+    sandboxPrototype: contentWindow,
+    wantXrays: true,
+    isWebExtensionContentScript: true,
+    wantGlobalProperties: ["XMLHttpRequest"],
+  });
 
   let delegate = {
     getSender(context, target, sender) {
@@ -283,19 +265,12 @@ function ExtensionContext(extensionId, contentWindow, contextOptions = {}) {
   let filter = {extensionId, frameId};
   this.messenger = new Messenger(this, broker, sender, filter, delegate);
 
-  this.chromeObj = Cu.createObjectIn(this.sandbox, {defineAs: "browser"});
+  let chromeObj = Cu.createObjectIn(this.sandbox, {defineAs: "browser"});
 
   // Sandboxes don't get Xrays for some weird compatibility
   // reason. However, we waive here anyway in case that changes.
-  Cu.waiveXrays(this.sandbox).chrome = this.chromeObj;
-
-  injectAPI(api(this), this.chromeObj);
-
-  // This is an iframe with content script API enabled. (See Bug 1214658 for rationale)
-  if (isExtensionPage) {
-    Cu.waiveXrays(this.contentWindow).chrome = this.chromeObj;
-    Cu.waiveXrays(this.contentWindow).browser = this.chromeObj;
-  }
+  Cu.waiveXrays(this.sandbox).chrome = Cu.waiveXrays(this.sandbox).browser;
+  injectAPI(api(this), chromeObj);
 }
 
 ExtensionContext.prototype = {
@@ -319,17 +294,7 @@ ExtensionContext.prototype = {
     for (let obj of this.onClose) {
       obj.close();
     }
-
-    // Overwrite the content script APIs with an empty object if the APIs objects are still
-    // defined in the content window (See Bug 1214658 for rationale).
-    if (this.isExtensionPage && !Cu.isDeadWrapper(this.contentWindow) &&
-        Cu.waiveXrays(this.contentWindow).browser === this.chromeObj) {
-      Cu.createObjectIn(this.contentWindow, { defineAs: "browser" });
-      Cu.createObjectIn(this.contentWindow, { defineAs: "chrome" });
-    }
-
     Cu.nukeSandbox(this.sandbox);
-    this.sandbox = null;
   },
 };
 
@@ -345,10 +310,7 @@ var DocumentManager = {
   extensionCount: 0,
 
   // Map[windowId -> Map[extensionId -> ExtensionContext]]
-  contentScriptWindows: new Map(),
-
-  // Map[windowId -> ExtensionContext]
-  extensionPageWindows: new Map(),
+  windows: new Map(),
 
   init() {
     Services.obs.addObserver(this, "document-element-inserted", false);
@@ -386,40 +348,23 @@ var DocumentManager = {
         return;
       }
 
-      // Enable the content script APIs should be available in subframes' window
-      // if it is recognized as a valid addon id (see Bug 1214658 for rationale).
-      const { CONTENTSCRIPT_PRIVILEGES } = ExtensionManagement.API_LEVELS;
-      let extensionId = ExtensionManagement.getAddonIdForWindow(window);
-
-      if (ExtensionManagement.getAPILevelForWindow(window, extensionId) == CONTENTSCRIPT_PRIVILEGES &&
-          ExtensionManager.get(extensionId)) {
-        DocumentManager.getExtensionPageContext(extensionId, window);
-      }
-
       this.trigger("document_start", window);
       /* eslint-disable mozilla/balanced-listeners */
       window.addEventListener("DOMContentLoaded", this, true);
       window.addEventListener("load", this, true);
       /* eslint-enable mozilla/balanced-listeners */
     } else if (topic == "inner-window-destroyed") {
-      let windowId = subject.QueryInterface(Ci.nsISupportsPRUint64).data;
-
-      // Close any existent content-script context for the destroyed window.
-      if (this.contentScriptWindows.has(windowId)) {
-        let extensions = this.contentScriptWindows.get(windowId);
-        for (let [, context] of extensions) {
-          context.close();
-        }
-
-        this.contentScriptWindows.delete(windowId);
+      let id = subject.QueryInterface(Ci.nsISupportsPRUint64).data;
+      if (!this.windows.has(id)) {
+        return;
       }
 
-      // Close any existent iframe extension page context for the destroyed window.
-      if (this.extensionPageWindows.has(windowId)) {
-        let context = this.extensionWindows.get(windowId);
+      let extensions = this.windows.get(id);
+      for (let [, context] of extensions) {
         context.close();
-        this.extensionPageWindows.delete(windowId);
       }
+
+      this.windows.delete(id);
     }
   },
 
@@ -444,7 +389,7 @@ var DocumentManager = {
 
   executeScript(global, extensionId, script) {
     let window = global.content;
-    let context = this.getContentScriptContext(extensionId, window);
+    let context = this.getContext(extensionId, window);
     if (!context) {
       return;
     }
@@ -468,33 +413,19 @@ var DocumentManager = {
     }
   },
 
-  getContentScriptContext(extensionId, window) {
+  getContext(extensionId, window) {
     let winId = windowId(window);
-    if (!this.contentScriptWindows.has(winId)) {
-      this.contentScriptWindows.set(winId, new Map());
+    if (!this.windows.has(winId)) {
+      this.windows.set(winId, new Map());
     }
-
-    let extensions = this.contentScriptWindows.get(winId);
+    let extensions = this.windows.get(winId);
     if (!extensions.has(extensionId)) {
       let context = new ExtensionContext(extensionId, window);
       extensions.set(extensionId, context);
     }
-
     return extensions.get(extensionId);
   },
 
-  getExtensionPageContext(extensionId, window) {
-    let winId = windowId(window);
-
-    let context = this.extensionPageWindows.get(winId);
-    if (!context) {
-      let context = new ExtensionContext(extensionId, window, { isExtensionPage: true });
-      this.extensionPageWindows.set(winId, context);
-    }
-
-    return context;
-  },
-
   startupExtension(extensionId) {
     if (this.extensionCount == 0) {
       this.init();
@@ -509,7 +440,7 @@ var DocumentManager = {
       for (let [window, state] of this.enumerateWindows(global.docShell)) {
         for (let script of extension.scripts) {
           if (script.matches(window)) {
-            let context = this.getContentScriptContext(extensionId, window);
+            let context = this.getContext(extensionId, window);
             context.execute(script, scheduled => isWhenBeforeOrSame(scheduled, state));
           }
         }
@@ -518,8 +449,7 @@ var DocumentManager = {
   },
 
   shutdownExtension(extensionId) {
-    // Clean up content-script contexts on extension shutdown.
-    for (let [, extensions] of this.contentScriptWindows) {
+    for (let [, extensions] of this.windows) {
       let context = extensions.get(extensionId);
       if (context) {
         context.close();
@@ -527,14 +457,6 @@ var DocumentManager = {
       }
     }
 
-    // Clean up iframe extension page contexts on extension shutdown.
-    for (let [winId, context] of this.extensionPageWindows) {
-      if (context.extensionId == extensionId) {
-        context.close();
-        this.extensionPageWindows.delete(winId);
-      }
-    }
-
     this.extensionCount--;
     if (this.extensionCount == 0) {
       this.uninit();
@@ -546,7 +468,7 @@ var DocumentManager = {
     for (let [extensionId, extension] of ExtensionManager.extensions) {
       for (let script of extension.scripts) {
         if (script.matches(window)) {
-          let context = this.getContentScriptContext(extensionId, window);
+          let context = this.getContext(extensionId, window);
           context.execute(script, scheduled => scheduled == state);
         }
       }
diff --git a/toolkit/components/extensions/ExtensionManagement.jsm b/toolkit/components/extensions/ExtensionManagement.jsm
index 58f1b9758992..36c29a783050 100644
--- a/toolkit/components/extensions/ExtensionManagement.jsm
+++ b/toolkit/components/extensions/ExtensionManagement.jsm
@@ -202,58 +202,18 @@ var Service = {
   // This is used to set the addonId on the originAttributes for the
   // nsIPrincipal attached to the URI.
   extensionURIToAddonID(uri) {
+    if (this.extensionURILoadableByAnyone(uri)) {
+      // We don't want webAccessibleResources to be associated with
+      // the add-on. That way they don't get any special privileges.
+      return null;
+    }
+
     let uuid = uri.host;
     let extension = this.uuidMap.get(uuid);
     return extension ? extension.id : undefined;
   },
 };
 
-// API Levels Helpers
-
-// Find the add-on associated with this document via the
-// principal's originAttributes. This value is computed by
-// extensionURIToAddonID, which ensures that we don't inject our
-// API into webAccessibleResources or remote web pages.
-function getAddonIdForWindow(window) {
-  let principal = window.document.nodePrincipal;
-  return principal.originAttributes.addonId;
-}
-
-const API_LEVELS = Object.freeze({
-  NO_PRIVILEGES: 0,
-  CONTENTSCRIPT_PRIVILEGES: 1,
-  FULL_PRIVILEGES: 2,
-});
-
-// Finds the API Level ("FULL_PRIVILEGES", "CONTENTSCRIPT_PRIVILEGES", "NO_PRIVILEGES")
-// with a given a window object.
-function getAPILevelForWindow(window, addonId) {
-  const { NO_PRIVILEGES, CONTENTSCRIPT_PRIVILEGES, FULL_PRIVILEGES } = API_LEVELS;
-
-  // Non WebExtension URLs and WebExtension URLs from a different extension
-  // has no access to APIs.
-  if (!addonId && getAddonIdForWindow(window) != addonId) {
-    return NO_PRIVILEGES;
-  }
-
-  let docShell = window.QueryInterface(Ci.nsIInterfaceRequestor)
-        .getInterface(Ci.nsIDocShell);
-
-  // WebExtension URLs loaded into sub-frame UI have "content script API level privileges".
-  // (see Bug 1214658 for rationale)
-  if (docShell.sameTypeParent) {
-    return CONTENTSCRIPT_PRIVILEGES;
-  }
-
-  // Extension pages running in the content process defaults to "content script API level privileges".
-  if (Services.appinfo.processType == Services.appinfo.PROCESS_TYPE_CONTENT) {
-    return CONTENTSCRIPT_PRIVILEGES;
-  }
-
-  // WebExtension URLs loaded into top frames UI could have full API level privileges.
-  return FULL_PRIVILEGES;
-}
-
 this.ExtensionManagement = {
   startupExtension: Service.startupExtension.bind(Service),
   shutdownExtension: Service.shutdownExtension.bind(Service),
@@ -266,9 +226,4 @@ this.ExtensionManagement = {
 
   getFrameId: Frames.getId.bind(Frames),
   getParentFrameId: Frames.getParentId.bind(Frames),
-
-  // exported API Level Helpers
-  getAddonIdForWindow,
-  getAPILevelForWindow,
-  API_LEVELS,
 };
diff --git a/toolkit/components/extensions/test/mochitest/file_ext_test_api_injection.js b/toolkit/components/extensions/test/mochitest/file_ext_background_api_injection.js
similarity index 100%
rename from toolkit/components/extensions/test/mochitest/file_ext_test_api_injection.js
rename to toolkit/components/extensions/test/mochitest/file_ext_background_api_injection.js
diff --git a/toolkit/components/extensions/test/mochitest/mochitest.ini b/toolkit/components/extensions/test/mochitest/mochitest.ini
index aed909db6a60..f1364edefce2 100644
--- a/toolkit/components/extensions/test/mochitest/mochitest.ini
+++ b/toolkit/components/extensions/test/mochitest/mochitest.ini
@@ -20,15 +20,13 @@ support-files =
   file_sample.html
   redirection.sjs
   file_privilege_escalation.html
-  file_ext_test_api_injection.js
+  file_ext_background_api_injection.js
   file_permission_xhr.html
 
 [test_ext_simple.html]
 [test_ext_geturl.html]
 [test_ext_contentscript.html]
 skip-if = buildapp == 'b2g' # runat != document_idle is not supported.
-[test_ext_contentscript_create_iframe.html]
-[test_ext_contentscript_api_injection.html]
 [test_ext_i18n_css.html]
 [test_ext_generate.html]
 [test_ext_localStorage.html]
diff --git a/toolkit/components/extensions/test/mochitest/test_ext_background_api_injection.html b/toolkit/components/extensions/test/mochitest/test_ext_background_api_injection.html
index 45d2290cc94c..b5f76022f190 100644
--- a/toolkit/components/extensions/test/mochitest/test_ext_background_api_injection.html
+++ b/toolkit/components/extensions/test/mochitest/test_ext_background_api_injection.html
@@ -25,7 +25,7 @@ add_task(function* testBackgroundWindow() {
 
   let awaitConsole = new Promise(resolve => {
     let chromeScript = SpecialPowers.loadChromeScript(
-      SimpleTest.getTestFileURL("file_ext_test_api_injection.js"));
+      SimpleTest.getTestFileURL("file_ext_background_api_injection.js"));
 
     chromeScript.addMessageListener("console-message", resolve);
   });
diff --git a/toolkit/components/extensions/test/mochitest/test_ext_contentscript_api_injection.html b/toolkit/components/extensions/test/mochitest/test_ext_contentscript_api_injection.html
deleted file mode 100644
index 42ea42575ce8..000000000000
--- a/toolkit/components/extensions/test/mochitest/test_ext_contentscript_api_injection.html
+++ /dev/null
@@ -1,88 +0,0 @@
-<!DOCTYPE HTML>
-<html>
-<head>
-  <title>Test for privilege escalation into iframe with content script APIs</title>
-  <script type="text/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
-  <script type="text/javascript" src="/tests/SimpleTest/SpawnTask.js"></script>
-  <script type="text/javascript" src="/tests/SimpleTest/ExtensionTestUtils.js"></script>
-  <script type="text/javascript" src="head.js"></script>
-  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
-</head>
-<body>
-
-<!-- WORKAROUND: this textarea hack is used to contain the html page source without escaping it -->
-<textarea id="test-asset">
-  <!DOCTYPE HTML>
-  <html>
-    <head>
-      <meta charset="utf-8">
-      <script type="text/javascript" src="./content_script_iframe.js">
-      </script>
-    </head>
-  </html>
-</textarea>
-
-<script type="text/javascript">
-"use strict";
-
-add_task(function* test_contentscript_api_injection() {
-  function contentScript() {
-    let iframe = document.createElement("iframe");
-    iframe.setAttribute("src", browser.runtime.getURL("content_script_iframe.html"));
-    document.body.appendChild(iframe);
-  }
-
-  function contentScriptIframe() {
-    const BASE = "http://mochi.test:8888/tests/toolkit/components/extensions/test/mochitest";
-    window.location = `${BASE}/file_privilege_escalation.html`;
-  }
-
-  let extensionData = {
-    manifest: {
-      content_scripts: [
-        {
-          "matches": ["http://mochi.test/*/file_sample.html"],
-          "js": ["content_script.js"],
-          "run_at": "document_end",
-        },
-      ],
-      "web_accessible_resources": [
-        "content_script_iframe.html",
-      ],
-    },
-
-    files: {
-      "content_script.js": "new " + contentScript,
-      "content_script_iframe.js": "new " + contentScriptIframe,
-      "content_script_iframe.html": document.querySelector("#test-asset").textContent,
-    },
-  };
-
-  let extension = ExtensionTestUtils.loadExtension(extensionData);
-
-  let awaitConsole = new Promise(resolve => {
-    let chromeScript = SpecialPowers.loadChromeScript(
-      SimpleTest.getTestFileURL("file_ext_test_api_injection.js"));
-
-    chromeScript.addMessageListener("console-message", resolve);
-  });
-
-  yield extension.startup();
-  info("extension loaded");
-
-  let win = window.open("file_sample.html");
-
-  let message = yield awaitConsole;
-
-  ok(message.message.includes("WebExt Privilege Escalation: typeof(browser) = undefined"),
-     "Document does not have `browser` APIs.");
-
-  win.close();
-
-  yield extension.unload();
-  info("extension unloaded");
-});
-</script>
-
-</body>
-</html>
diff --git a/toolkit/components/extensions/test/mochitest/test_ext_contentscript_create_iframe.html b/toolkit/components/extensions/test/mochitest/test_ext_contentscript_create_iframe.html
deleted file mode 100644
index 3c8028023c87..000000000000
--- a/toolkit/components/extensions/test/mochitest/test_ext_contentscript_create_iframe.html
+++ /dev/null
@@ -1,163 +0,0 @@
-<!DOCTYPE HTML>
-<html>
-<head>
-  <title>Test for content script</title>
-  <script type="text/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
-  <script type="text/javascript" src="/tests/SimpleTest/SpawnTask.js"></script>
-  <script type="text/javascript" src="/tests/SimpleTest/ExtensionTestUtils.js"></script>
-  <script type="text/javascript" src="head.js"></script>
-  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
-</head>
-<body>
-
-<!-- WORKAROUND: this textarea hack is used to contain the html page source without escaping it -->
-<textarea id="test-asset">
-  <!DOCTYPE HTML>
-  <html>
-    <head>
-      <meta charset="utf-8">
-      <script type="text/javascript" src="content_script_iframe.js"></script>
-    </head>
-  </html>
-</textarea>
-
-<script type="text/javascript">
-"use strict";
-
-add_task(function* test_contentscript_create_iframe() {
-  function backgroundScript() {
-    browser.runtime.onMessage.addListener((msg, sender) => {
-      let { name, availableAPIs, manifest, testGetManifest } = msg;
-      let hasExtTabsAPI = availableAPIs.indexOf("tabs") > 0;
-      let hasExtWindowsAPI = availableAPIs.indexOf("windows") > 0;
-
-      browser.test.assertFalse(hasExtTabsAPI, "the created iframe should not be able to use privileged APIs (tabs)");
-      browser.test.assertFalse(hasExtWindowsAPI, "the created iframe should not be able to use privileged APIs (windows)");
-
-      let { applications: { gecko: { id: expectedManifestGeckoId } } } = chrome.runtime.getManifest();
-      let { applications: { gecko: { id: actualManifestGeckoId } } } = manifest;
-
-      browser.test.assertEq(actualManifestGeckoId, expectedManifestGeckoId,
-                            "the add-on manifest should be accessible from the created iframe"
-      );
-
-      let { applications: { gecko: { id: testGetManifestGeckoId } } } = testGetManifest;
-
-      browser.test.assertEq(testGetManifestGeckoId, expectedManifestGeckoId,
-                              "GET_MANIFEST() returns manifest data before extension unload"
-      );
-
-      browser.test.sendMessage(name);
-    });
-  }
-
-  function contentScript() {
-    let iframe = document.createElement("iframe");
-    iframe.setAttribute("src", browser.runtime.getURL("content_script_iframe.html"));
-    document.body.appendChild(iframe);
-  }
-
-  function contentScriptIframe() {
-    window.GET_MANIFEST = browser.runtime.getManifest.bind(null);
-
-    window.testGetManifestException = () => {
-      try {
-        window.GET_MANIFEST();
-      } catch (exception) {
-        return String(exception);
-      }
-    };
-
-    let testGetManifest = window.GET_MANIFEST();
-
-    let manifest = browser.runtime.getManifest();
-    let availableAPIs = Object.keys(browser);
-
-    browser.runtime.sendMessage({
-      name: "content-script-iframe-loaded",
-      availableAPIs,
-      manifest,
-      testGetManifest,
-    });
-  }
-
-  let extensionData = {
-    manifest: {
-      content_scripts: [
-        {
-          "matches": ["http://mochi.test/*/file_sample.html"],
-          "js": ["content_script.js"],
-          "run_at": "document_end",
-        },
-      ],
-      web_accessible_resources: [
-        "content_script_iframe.html",
-      ],
-    },
-
-    background: "(" + backgroundScript + ")()",
-
-    files: {
-      "content_script.js": "new " + contentScript,
-      "content_script_iframe.html": document.querySelector("#test-asset").textContent,
-      "content_script_iframe.js": "new " + contentScriptIframe,
-    },
-  };
-
-  let extension = ExtensionTestUtils.loadExtension(extensionData);
-
-  let contentScriptIframeCreatedPromise = new Promise(resolve => {
-    extension.onMessage("content-script-iframe-loaded", () => { resolve(); });
-  });
-
-  yield extension.startup();
-  info("extension loaded");
-
-  let win = window.open("file_sample.html");
-
-  yield Promise.all([waitForLoad(win), contentScriptIframeCreatedPromise]);
-  info("content script privileged iframe loaded and executed");
-
-  info("testing APIs availability once the extension is unloaded...");
-
-  let iframeWindow = SpecialPowers.wrap(win)[0];
-
-  ok(iframeWindow, "content script enabled iframe found");
-  ok(/content_script_iframe\.html$/.test(iframeWindow.location), "the found iframe has the expected URL");
-
-  yield extension.unload();
-  info("extension unloaded");
-
-  info("test content script APIs not accessible from the frame once the extension is unloaded");
-
-  let ww = SpecialPowers.Cu.waiveXrays(iframeWindow);
-  let isDeadWrapper = SpecialPowers.Cu.isDeadWrapper(ww.browser);
-  ok(!isDeadWrapper, "the API object should not be a dead object");
-
-  let manifest;
-  let manifestException;
-
-  try {
-    manifest = ww.browser.runtime.getManifest();
-  } catch (e) {
-    manifestException = e;
-  }
-
-  ok(!manifest, "manifest should be undefined");
-
-  is(String(manifestException), "TypeError: ww.browser.runtime is undefined",
-     "expected \"TypeError: ... is undefined\" exception received");
-
-  let getManifestException = ww.testGetManifestException();
-
-  is(getManifestException, "TypeError: window.GET_MANIFEST is not a function",
-     "expected \"TypeError: ... is not a function\" exception received");
-
-  win.close();
-
-  info("done");
-});
-</script>
-
-</body>
-</html>