Returns the extension matching |extension_id| or NULL if no matching
extension is accessible in this context (see HasExtension). This function
must be called on the browser process UI thread.
WARNING: This function is deprecated and will be removed in ~M127.
Returns the extension matching |extension_id| or NULL if no matching extension is accessible in this context (see HasExtension). This function must be called on the browser process UI thread.
WARNING: This function is deprecated and will be removed in ~M127.