Do not show autofill++ or saved form data in incognito mode.

Bug:2968399

Also do not save the form data in incognito mode.

Change-Id: Ice6a1cb3620b5cf272b6b361ce11f8abef269a89

core/java/android/webkit/WebSettings.java

@@ -657,10 +657,11 @@ public class WebSettings {
     }
 
     /**
-     *  Return whether the WebView is saving form data.
+     *  Return whether the WebView is saving form data and displaying prior
+     *  entries/autofill++.  Always false in private browsing mode.
      */
     public boolean getSaveFormData() {
-        return mSaveFormData;
+        return mSaveFormData && !mPrivateBrowsingEnabled;
     }
 
     /**