17308 Flush background canvas before allocating a new surface (cla: yes)

17309 Roll src/third_party/skia 6beb1dd941af..4261fe753b77 (3 commits) (cla: yes, waiting for tree to go green)

17312 Remove JSON codec from C++ client wrapper (cla: yes)

17313 fuchsia: remove use of replace_as_executable (second try) (cla: yes)

17314 Roll src/third_party/skia 4261fe753b77..9686528ac8c7 (1 commits) (cla: yes, waiting for tree to go green)

17315 Roll fuchsia/sdk/core/mac-amd64 from Lzj3Z… to o8vhc… (cla: yes, waiting for tree to go green)