Show a different warning for PDF’s with forms.

extensions/firefox/components/PdfStreamConverter.js

@@ -377,11 +377,16 @@ ChromeActions.prototype = {
         break;
     }
   },
-  fallback: function(url, sendResponse) {
+  fallback: function(featureId, url, sendResponse) {
     var self = this;
     var domWindow = this.domWindow;
     var strings = getLocalizedStrings('chrome.properties');
-    var message = getLocalizedString(strings, 'unsupported_feature');
+    var message;
+    if (featureId === 'forms') {
+      message = getLocalizedString(strings, 'unsupported_feature_forms');
+    } else {
+      message = getLocalizedString(strings, 'unsupported_feature');
+    }
 
     PdfJsTelemetry.onFallback();
 

l10n/en-US/chrome.properties

@@ -14,5 +14,6 @@
 
 # Chrome notification bar messages and buttons
 unsupported_feature=This PDF document might not be displayed correctly.
+unsupported_feature_forms=This PDF document contains forms. The filling of form fields is not supported.
 open_with_different_viewer=Open With Different Viewer
 open_with_different_viewer.accessKey=o

web/viewer.js

@@ -609,7 +609,7 @@ var PDFView = {
 //    return;
 //  this.fellback = true;
 //  var url = this.url.split('#')[0];
-//  FirefoxCom.request('fallback', url, function response(download) {
+//  FirefoxCom.request('fallback', featureId, url, function response(download) {
 //    if (!download)
 //      return;
 //    PDFView.download();