Add a prompt dialog test

This test will dismiss a prompt type dialog box.

Author: ankur22

tests/frame_test.go

@@ -36,6 +36,9 @@ func TestFrameDismissDialogBox(t *testing.T) {
 		{
 			name: "confirm",
 		},
+		{
+			name: "prompt",
+		},
 	}
 
 	for _, tt := range tests {

tests/static/dialog.html

@@ -11,6 +11,8 @@
                     break;
                 case "confirm":
                     confirm("Click accept")
+                case "prompt":
+                    prompt("Add text and then click accept")
             }
         </script>
     </head>