Introduce BeginShutdown() (declared in header) and move window-close shutdown logic into it. OnWindowCloseRequested and chrome close/exit handlers now call BeginShutdown; shutdown now collects closing_tab_browsers_ plus any active tab browsers into a single list before closing them. MaybeFinishShutdown was updated to consider closing_tab_browsers_ so shutdown won't finish prematurely. This centralizes shutdown behavior and ensures all relevant browser instances are closed cleanly.
Andrew Zambazos
659d1530b0