Created an HtmlInfo object on ViewStructure.

The ViewStructure typically represents a View, but it it can also be a virtual
view; in particular, WebView uses virtual views to represent HTML elements.

Although most of the properties of the HTML element maps to properties of
Android Views, some properties (such as 'name' and 'id' on <INPUT> fields)
don't, and those are crucial for autofilling web pages.

Rather than trying to artificially map these properties, it's better to create
a generic representation, for the following reasons:

1. Web standards move in a different velocity than Android APIs
2. Android APIs cannot be changed easily. Deprecated APIs continue to work,
   and new added APIs don't work in older versions
3. The data used for autofill is opaque to the Framework - it's only relevant
   to the node producers (like WebView) and consumers (Autofill services).

Also removed the setIdEntry() that was used for the same purpose.

Fixes: 36696757
Bug: 36718508
Test: VirtualContainerActivityTest with new checks pass

Change-Id: Ia626bd1f640b0b5861e81a5915504b95029874c9