Found a potentially leaking cycle starting from a GC root:
./cycle_ptrs.h:49:5: blink::E (m_a) => blink::A
./cycle_ptrs.h:26:5: blink::A (m_b) => blink::B
./cycle_ptrs.h:34:5: blink::B (m_c) => blink::C
./cycle_ptrs.h:39:5: blink::C (m_d) => blink::D
./cycle_ptrs.h:44:5: blink::D (m_es) => blink::E