Description

When an inline attachment is open, it should still be open when the page is refreshed. An error is thrown. Since the openAttachment method was removed from amp-story-page.

Reproduction Steps

1. Open a story with an attachment such as /examples/amp-story/attachment.html.
2. open an inline attachment.
3. refresh page.

Relevant Logs

error-reporting.js:203 TypeError: _this6.activePage_.openAttachment is not a function
    at amp-story.js:949:28

Browser(s) Affected

No response

OS(s) Affected

all

Device(s) Affected

all

AMP Version Affected

No response