diff --git a/dom/apps/src/AppsUtils.jsm b/dom/apps/src/AppsUtils.jsm
index 1a2ee6c277c3..18dc38bc2dd1 100644
--- a/dom/apps/src/AppsUtils.jsm
+++ b/dom/apps/src/AppsUtils.jsm
@@ -47,7 +47,9 @@ this.AppsUtils = {
       downloadSize: aApp.downloadSize || 0,
       lastUpdateCheck: aApp.lastUpdateCheck,
       updateTime: aApp.updateTime,
-      etag: aApp.etag
+      etag: aApp.etag,
+      installerAppId: aApp.installerAppId || Ci.nsIScriptSecurityManager.NO_APP_ID,
+      installerIsBrowser: !!aApp.installerIsBrowser
     };
   },
 
diff --git a/dom/apps/src/Webapps.js b/dom/apps/src/Webapps.js
index f7071ffa98a1..cc176a3e8eb0 100644
--- a/dom/apps/src/Webapps.js
+++ b/dom/apps/src/Webapps.js
@@ -97,6 +97,7 @@ WebappsRegistry.prototype = {
                       Array.isArray(aParams.categories)) ? aParams.categories
                                                          : [];
 
+    let principal = this._window.document.nodePrincipal;
     cpmm.sendAsyncMessage("Webapps:Install",
                           { app: {
                               installOrigin: this._getOrigin(installURL),
@@ -107,7 +108,9 @@ WebappsRegistry.prototype = {
                             },
                             from: installURL,
                             oid: this._id,
-                            requestID: requestID
+                            requestID: requestID,
+                            appId: principal.appId,
+                            isBrowser: principal.isInBrowserElement
                           });
     return request;
   },
@@ -168,6 +171,7 @@ WebappsRegistry.prototype = {
                       Array.isArray(aParams.categories)) ? aParams.categories
                                                          : [];
 
+    let principal = this._window.document.nodePrincipal;
     cpmm.sendAsyncMessage("Webapps:InstallPackage",
                           { app: {
                               installOrigin: this._getOrigin(installURL),
@@ -179,7 +183,9 @@ WebappsRegistry.prototype = {
                             from: installURL,
                             oid: this._id,
                             requestID: requestID,
-                            isPackage: true
+                            isPackage: true,
+                            appId: principal.appId,
+                            isBrowser: principal.isInBrowserElement
                           });
     return request;
   },
diff --git a/dom/apps/src/Webapps.jsm b/dom/apps/src/Webapps.jsm
index 96ad1053025a..0d6f01d4d9ef 100644
--- a/dom/apps/src/Webapps.jsm
+++ b/dom/apps/src/Webapps.jsm
@@ -123,6 +123,14 @@ this.DOMApplicationRegistry = {
             if (this.webapps[id].appStatus === undefined) {
               this.webapps[id].appStatus = Ci.nsIPrincipal.APP_STATUS_INSTALLED;
             }
+
+            // Default to NO_APP_ID and not in browser.
+            if (this.webapps[id].installerAppId === undefined) {
+              this.webapps[id].installerAppId = Ci.nsIScriptSecurityManager.NO_APP_ID;
+            }
+            if (this.webapps[id].installerIsBrowser === undefined) {
+              this.webapps[id].installerIsBrowser = false;
+            }
           };
         }
         aNext();
@@ -1162,6 +1170,8 @@ this.DOMApplicationRegistry = {
     if (app.etag) {
       xhr.setRequestHeader("If-None-Match", app.etag);
     }
+    xhr.channel.notificationCallbacks =
+      this.createLoadContext(app.installerAppId, app.installerIsBrowser);
 
     xhr.addEventListener("load", (function() {
       if (xhr.status == 200) {
@@ -1205,6 +1215,31 @@ this.DOMApplicationRegistry = {
     xhr.send(null);
   },
 
+  // Creates a nsILoadContext object with a given appId and isBrowser flag.
+  createLoadContext: function createLoadContext(aAppId, aIsBrowser) {
+    return LoadContextCallback = {
+       associatedWindow: null,
+       topWindow : null,
+       appId: aAppId,
+       isInBrowserElement: aIsBrowser,
+       usePrivateBrowsing: false,
+       isContent: false,
+
+       isAppOfType: function(appType) {
+         throw Cr.NS_ERROR_NOT_IMPLEMENTED;
+       },
+
+       QueryInterface: XPCOMUtils.generateQI([Ci.nsILoadContext,
+                                              Ci.nsIInterfaceRequestor,
+                                              Ci.nsISupports]),
+       getInterface: function(iid) {
+         if (iid.equals(Ci.nsILoadContext))
+           return this;
+         throw Cr.NS_ERROR_NO_INTERFACE;
+       }
+     }
+  },
+
   // Downloads the manifest and run checks, then eventually triggers the
   // installation UI.
   doInstall: function doInstall(aData, aMm) {
@@ -1229,7 +1264,10 @@ this.DOMApplicationRegistry = {
                 .createInstance(Ci.nsIXMLHttpRequest);
     xhr.open("GET", app.manifestURL, true);
     xhr.channel.loadFlags |= Ci.nsIRequest.VALIDATE_ALWAYS;
+    xhr.channel.notificationCallbacks = this.createLoadContext(aData.appId,
+                                                               aData.isBrowser);
     xhr.responseType = "json";
+
     xhr.addEventListener("load", (function() {
       if (xhr.status == 200) {
         if (!AppsUtils.checkManifestContentType(app.installOrigin, app.origin,
@@ -1281,6 +1319,8 @@ this.DOMApplicationRegistry = {
                 .createInstance(Ci.nsIXMLHttpRequest);
     xhr.open("GET", app.manifestURL, true);
     xhr.channel.loadFlags |= Ci.nsIRequest.VALIDATE_ALWAYS;
+    xhr.channel.notificationCallbacks = this.createLoadContext(aData.appId,
+                                                               aData.isBrowser);
     xhr.responseType = "json";
 
     xhr.addEventListener("load", (function() {
@@ -1413,6 +1453,9 @@ this.DOMApplicationRegistry = {
     appObject.name = manifest.name;
     appObject.csp = manifest.csp || "";
 
+    appObject.installerAppId = aData.appId;
+    appObject.installerIsBrowser = aData.isBrowser;
+
     this.webapps[id] = appObject;
 
     // For package apps, the permissions are not in the mini-manifest, so
@@ -1649,7 +1692,8 @@ this.DOMApplicationRegistry = {
       requestChannel.notificationCallbacks = {
         QueryInterface: function notifQI(aIID) {
           if (aIID.equals(Ci.nsISupports)          ||
-              aIID.equals(Ci.nsIProgressEventSink))
+              aIID.equals(Ci.nsIProgressEventSink) ||
+              aIID.equals(Ci.nsILoadContext))
             return this;
 
           throw Cr.NS_ERROR_NO_INTERFACE;
@@ -1667,7 +1711,18 @@ this.DOMApplicationRegistry = {
                                   progress: aProgress,
                                   app: app });
         },
-        onStatus: function notifStatus(aRequest, aContext, aStatus, aStatusArg) { }
+        onStatus: function notifStatus(aRequest, aContext, aStatus, aStatusArg) { },
+
+        // nsILoadContext
+        appId: app.installerAppId,
+        isInBrowserElement: app.installerIsBrowser,
+        usePrivateBrowsing: false,
+        isContent: false,
+        associatedWindow: null,
+        topWindow : null,
+        isAppOfType: function(appType) {
+          throw Cr.NS_ERROR_NOT_IMPLEMENTED;
+        }
       }
 
       // We set the 'downloading' flag to true right before starting the fetch.