28950 Fix typos in spirv README (cla: yes, waiting for tree to go green)

28951 [fuchsia] Pass WeakPtrs to GfxConnection FIDL fns. (cla: yes, waiting for tree to go green, platform-fuchsia, needs tests)

28952 Roll Skia from 58014fa9a6a0 to ddbb97d741ff (1 revision) (cla: yes, waiting for tree to go green)

28953 Roll Dart SDK from acbcdc91a2c8 to 54d42054bcb1 (1 revision) (cla: yes, waiting for tree to go green)

28954 Roll Fuchsia Mac SDK from owSIykHxQ… to Fo7RBTco3… (cla: yes, waiting for tree to go green)