SurfaceVisibleCallback 55 cc/test/test_context_support.cc const SurfaceVisibleCallback& set_visible_callback) { SurfaceVisibleCallback 42 cc/test/test_context_support.h const SurfaceVisibleCallback& set_visible_callback); SurfaceVisibleCallback 68 cc/test/test_context_support.h SurfaceVisibleCallback set_visible_callback_;