Frame identifiers have changed from int64_t to string type. This is due
to https://crbug.com/1502660 which removes access to frame routing IDs
in the renderer process. New cross-process frame identifiers are 160-bit
values (32-bit child process ID + 128-bit local frame token) and most
easily represented as strings. All other frame-related expectations and
behaviors remain the same.
Adds a new CefBrowserProcessHandler::OnAlreadyRunningAppRelaunch
callback for when an already running app is relaunched with the
same CefSettings.root_cache_path.
Client apps should check the CefInitialize() return value for early
exit of the relaunch source process.
Marshall Greenblatt