Added a blob-href directive.

Added a blob-href directive to allow Angular to assign
attachment blob: URLs to <a href>.

chrome/app.js

@@ -24,6 +24,7 @@ goog.require('e2email.components.appinfo.module');
 goog.require('e2email.components.auth.module');
 goog.require('e2email.components.autocomplete.module');
 goog.require('e2email.components.autocompletedirective.module');
+goog.require('e2email.components.blobhrefdirective.module');
 goog.require('e2email.components.contacts.module');
 goog.require('e2email.components.gmail.module');
 goog.require('e2email.components.openpgp.module');
@@ -144,6 +145,7 @@ e2email.application.module = angular.module('e2email.application', [
   e2email.components.translatefilter.module.name,
   e2email.components.userinfo.module.name,
   e2email.components.userlist.module.name,
+  e2email.components.blobhrefdirective.module.name,
   'ngAnimate',
   'ngAria',
   'ngRoute'

chrome/components/blobhref/blobhref-directive.js

@@ -0,0 +1,40 @@
+goog.provide('e2email.components.blobhrefdirective');
+goog.provide('e2email.components.blobhrefdirective.module');
+
+goog.require('goog.string');
+
+
+goog.scope(function() {
+
+
+/**
+ * Directive that puts a blob: URL into an href attribute.
+ * Directive has to be used as blob: URLs are untrusted by Angular.
+ * See https://docs.angularjs.org/api/ng/provider/$compileProvider
+ * @return {!angular.Directive}
+ */
+e2email.components.blobhrefdirective.Directive =
+    function() {
+  return {
+    link: function(scope, element, attrs) {
+      if (goog.string.startsWith(attrs['blobHref'], 'blob:')) {
+        angular.element(element[0]).attr('href', attrs['blobHref']);
+      }
+    },
+    restrict: 'A',
+  };
+};
+
+
+/**
+ * Angular module.
+ * @type {!angular.Module}
+ */
+e2email.components.blobhrefdirective.module = angular
+    .module(
+        'e2email.components.blobhrefdirective.FixDownloadLinkDirective',
+        [])
+    .directive(
+        'blobHref',
+        e2email.components.blobhrefdirective.Directive);
+});  // goog.scope