diff --git a/dom/apps/src/AppsUtils.jsm b/dom/apps/src/AppsUtils.jsm
index 75949671212..8d495ac1f2d 100644
--- a/dom/apps/src/AppsUtils.jsm
+++ b/dom/apps/src/AppsUtils.jsm
@@ -25,13 +25,6 @@ function debug(s) {
   //dump("-*- AppsUtils.jsm: " + s + "\n");
 }
 
-function isAbsoluteURI(aURI) {
-  let foo = Services.io.newURI("http://foo", null, null);
-  let bar = Services.io.newURI("http://bar", null, null);
-  return Services.io.newURI(aURI, null, foo).prePath != foo.prePath ||
-         Services.io.newURI(aURI, null, bar).prePath != bar.prePath;
-}
-
 this.AppsUtils = {
   // Clones a app, without the manifest.
   cloneAppObject: function cloneAppObject(aApp) {
@@ -168,13 +161,21 @@ this.AppsUtils = {
     if (aManifest.name == undefined)
       return false;
 
-    // launch_path, entry_points launch paths, message hrefs, and activity hrefs can't be absolute
-    if (aManifest.launch_path && isAbsoluteURI(aManifest.launch_path))
+    function isAbsolute(uri) {
+      // See bug 810551
+      let foo = Services.io.newURI("http://foo", null, null);
+      let bar = Services.io.newURI("http://bar", null, null);
+      return Services.io.newURI(uri, null, foo).prePath != foo.prePath ||
+             Services.io.newURI(uri, null, bar).prePath != bar.prePath;
+    }
+
+    // launch_path and entry_points launch paths can't be absolute
+    if (aManifest.launch_path && isAbsolute(aManifest.launch_path))
       return false;
 
     function checkAbsoluteEntryPoints(entryPoints) {
       for (let name in entryPoints) {
-        if (entryPoints[name].launch_path && isAbsoluteURI(entryPoints[name].launch_path)) {
+        if (entryPoints[name].launch_path && isAbsolute(entryPoints[name].launch_path)) {
           return true;
         }
       }
@@ -190,35 +191,6 @@ this.AppsUtils = {
       }
     }
 
-    if (aManifest.activities) {
-      for (let activityName in aManifest.activities) {
-        let activity = aManifest.activities[activityName];
-        if (activity.href && isAbsoluteURI(activity.href)) {
-          return false;
-        }
-      }
-    }
-
-    // |messages| is an array of items, where each item is either a string or
-    // a {name: href} object.
-    let messages = aManifest.messages;
-    if (messages) {
-      if (!Array.isArray(messages)) {
-        return false;
-      }
-      for (let item of aManifest.messages) {
-        if (typeof item == "object") {
-          let keys = Object.keys(item);
-          if (keys.length != 1) {
-            return false;
-          }
-          if (isAbsoluteURI(item[keys[0]])) {
-            return false;
-          }
-        }
-      }
-    }
-
     return true;
   },
 
@@ -335,6 +307,10 @@ this.AppsUtils = {
         return false;
       }
 
+      if (!dev1 && !dev2) {
+        return true;
+      }
+
       return (dev1.name === dev2.name && dev1.url === dev2.url);
     }
 
@@ -468,10 +444,6 @@ ManifestHelper.prototype = {
   },
 
   resolveFromOrigin: function(aURI) {
-    // This should be enforced higher up, but check it here just in case.
-    if (!isAbsoluteURI(aURI)) {
-      throw new Error("Webapps.jsm: non-relative URI passed to resolveFromOrigin");
-    }
     return this._origin.resolve(aURI);
   },
 
diff --git a/dom/apps/src/Webapps.jsm b/dom/apps/src/Webapps.jsm
index 9e849ba054d..61b6454f1a9 100644
--- a/dom/apps/src/Webapps.jsm
+++ b/dom/apps/src/Webapps.jsm
@@ -241,7 +241,6 @@ this.DOMApplicationRegistry = {
 
     // We copy this app to DIRECTORY_NAME/$aId, and set the base path as needed.
     let destDir = FileUtils.getDir(DIRECTORY_NAME, ["webapps", aId], true, true);
-    destDir.permissions = FileUtils.PERMS_DIRECTORY;
 
     ["application.zip", "update.webapp"]
       .forEach(function(aFile) {
@@ -250,7 +249,6 @@ this.DOMApplicationRegistry = {
         file.copyTo(destDir, aFile);
         let newFile = destDir.clone();
         newFile.append(aFile);
-        newFile.permissions = FileUtils.PERMS_FILE;
       });
 
     app.basePath = FileUtils.getDir(DIRECTORY_NAME, ["webapps"], true, true)
@@ -272,7 +270,6 @@ this.DOMApplicationRegistry = {
       let manifestFile = destDir.clone();
       manifestFile.append("manifest.webapp");
       zipReader.extract("manifest.webapp", manifestFile);
-      manifestFile.permissions = FileUtils.PERMS_FILE;
     } catch(e) {
       // If we are unable to extract the manifest, cleanup and remove this app.
       debug("Cleaning up: " + e);
@@ -408,16 +405,6 @@ this.DOMApplicationRegistry = {
         this.installSystemApps(onAppsLoaded);
       else
         onAppsLoaded();
-
-      // XXX: To be removed as soon as the app:// protocol is remoted.
-      // See Bug 819061
-      let dir = Cc["@mozilla.org/file/local;1"].createInstance(Ci.nsIFile);
-      dir.initWithPath("/data");
-      dir.permissions = parseInt("755", 8);
-      dir.append("local");
-      dir.permissions = parseInt("755", 8);
-      dir.append("webapps");
-      dir.permissions = parseInt("755", 8);
 #else
       onAppsLoaded();
 #endif
@@ -1540,7 +1527,6 @@ this.DOMApplicationRegistry = {
     appObject.localId = localId;
     appObject.basePath = FileUtils.getDir(DIRECTORY_NAME, ["webapps"], true, true).path;
     let dir = FileUtils.getDir(DIRECTORY_NAME, ["webapps", id], true, true);
-    dir.permissions = FileUtils.PERMS_DIRECTORY;
     let manFile = dir.clone();
     manFile.append(manifestName);
     let jsonManifest = aData.isPackage ? app.updateManifest : app.manifest;
@@ -1620,7 +1606,6 @@ this.DOMApplicationRegistry = {
         let zipFile = FileUtils.getFile("TmpD", ["webapps", aId, "application.zip"], true);
         let dir = FileUtils.getDir(DIRECTORY_NAME, ["webapps", aId], true, true);
         zipFile.moveTo(dir, "application.zip");
-        zipFile.permissions = FileUtils.PERMS_FILE;
         let tmpDir = FileUtils.getDir("TmpD", ["webapps", aId], true, true);
         try {
           tmpDir.remove(true);