Bug 282978 – [WebDriver][BiDi] Support getting the source for log.entryAdded events

• Component: WebDriver
• Status: NEW

[Lauro Moura]

Spec: https://w3c.github.io/webdriver-bidi/#get-the-source

To get the source given source realm:

   1. Let realm be the realm id for source realm.

   2. Let environment settings be the environment settings object whose realm execution context's Realm component is source realm.

   3. If environment settings has a associated Document:

       1. Let document be environment settings’ associated Document.

       2. Let navigable be document’s node navigable.

       3. Let navigable id be the navigable id for navigable if navigable is not null.

       Otherwise let navigable be null.

    4. Let source be a map matching the script.Source production with the realm field set to realm, and the context field set to navigable id if navigable is not null, or unset otherwise.

    5. Return source.

[Radar WebKit Bug Importer]

<rdar://problem/140187204>