Gets the id of the web view a focus subject refers to, if it refers to one: either the web view
itself (focusType: 'webView') or a web view's tab (focusType: 'tab' with
TAB_TYPE_WEBVIEW; a web view tab's id is the same as its WebViewId). Returns undefined
for focus subjects that do not refer to a web view.
Shared so every consumer that projects a focus subject to a web view id (e.g. the window
service's last-selected tracking and platform.openBookChapterControl) stays in lockstep when
focus subject shapes change.
Gets the id of the web view a focus subject refers to, if it refers to one: either the web view itself (
focusType: 'webView') or a web view's tab (focusType: 'tab'with TAB_TYPE_WEBVIEW; a web view tab's id is the same as itsWebViewId). Returnsundefinedfor focus subjects that do not refer to a web view.Shared so every consumer that projects a focus subject to a web view id (e.g. the window service's last-selected tracking and
platform.openBookChapterControl) stays in lockstep when focus subject shapes change.