Make DocInfo.pageViewId64 async

[dreamofabear]

Fixes #23988.

Bug introduced in: https://github.com/ampproject/amphtml/pull/23451/files#r314530969

Affects browsers that don't implement WebCrypto or Crypto.getRandomValues: https://caniuse.com/#search=getRandomValues

[zhouyx]

Thanks for the fix!

[zhouyx]

Does this mean we are relying on get pageViewId64() getting called after extensions service is ready?

[dreamofabear]

Only after it's registered which happens very soon afterwards in runtime.adopt().

[jridgewell]

Does this even need to be on document info?

[zhouyx]

@jridgewell Good point. Maybe not.

I do see one concern here. If this hasn't changed, FIE and the parent doc shares the same ampdoc instance. Maybe we should not store pageViewId within the DocInfo, as that shares the same id between FIE and parent doc.

Do you see this as the case? If so I think that's an issue we need to fix asap

[dreamofabear]

Maybe we should not store pageViewId within the DocInfo, as that shares the same id between FIE and parent doc.

This would also affect PAGE_VIEW_ID then, right? PAGE_VIEW_ID_64 isn't a whitelisted A4A variable but looks like PAGE_VIEW_ID is.

amphtml/extensions/amp-a4a/0.1/a4a-variable-source.js

Lines 26 to 71 in dcaf2ce

	const WHITELISTED_VARIABLES = [
	'AMPDOC_HOST',
	'AMPDOC_HOSTNAME',
	'AMPDOC_URL',
	'AMP_VERSION',
	'AVAILABLE_SCREEN_HEIGHT',
	'AVAILABLE_SCREEN_WIDTH',
	'BACKGROUND_STATE',
	'BROWSER_LANGUAGE',
	'CANONICAL_HOST',
	'CANONICAL_HOSTNAME',
	'CANONICAL_PATH',
	'CANONICAL_URL',
	'COUNTER',
	'DOCUMENT_CHARSET',
	'DOCUMENT_REFERRER',
	'FIRST_CONTENTFUL_PAINT',
	'FIRST_VIEWPORT_READY',
	'MAKE_BODY_VISIBLE',
	'PAGE_VIEW_ID',
	'RANDOM',
	'SCREEN_COLOR_DEPTH',
	'SCREEN_HEIGHT',
	'SCREEN_WIDTH',
	'SCROLL_HEIGHT',
	'SCROLL_LEFT',
	'SCROLL_TOP',
	'SCROLL_WIDTH',
	'SHARE_TRACKING_INCOMING',
	'SHARE_TRACKING_OUTGOING',
	'SOURCE_HOST',
	'SOURCE_HOSTNAME',
	'SOURCE_PATH',
	'SOURCE_URL',
	'TIMESTAMP',
	'TIMEZONE',
	'TIMEZONE_CODE',
	'TITLE',
	'TOTAL_ENGAGED_TIME',
	'USER_AGENT',
	'VARIANT',
	'VARIANTS',
	'VIEWER',
	'VIEWPORT_HEIGHT',
	'VIEWPORT_WIDTH',
	];

[zhouyx]

True, it should only affect PAGE_VEW_ID. cc @lannka Should page_view_id be supported in FIE?

[zhouyx]

Talked to @lannka offline, we will be sharing PAGE_VIEW_ID, and maybe PAGE_VIEW_ID_64 in the future upon request. This is good now