Add an event handler for the ContentLoading event. ContentLoading
triggers before any content is loaded, including scripts added with
AddScriptToExecuteOnDocumentCreated. ContentLoading does not trigger
if a same page navigation occurs (such as through fragment
navigations or history.pushState navigations). This operation
follows the NavigationStarting and precedes NavigationCompleted events.
Add an event handler for the ContentLoading event. ContentLoading triggers before any content is loaded, including scripts added with AddScriptToExecuteOnDocumentCreated. ContentLoading does not trigger if a same page navigation occurs (such as through fragment navigations or history.pushState navigations). This operation follows the NavigationStarting and precedes NavigationCompleted events.