21278 Roll Dart SDK from 8c45e2e29cb4 to 8bd3017291e5 (1 revision) (cla: yes, waiting for tree to go green)

21279 Roll Fuchsia Mac SDK from i2PBGu2n-… to WsUbW2ZnA… (cla: yes, waiting for tree to go green)

21298 implement decodeFromPixels (cla: yes, waiting for tree to go green)

21301 Do not create a TestGLSurface for software-only rendering in EmbedderTest (cla: yes, waiting for tree to go green)

21303 [iOS TextInput] Avoid Unnecessary UndateEditingClient Calls (cla: yes, platform-ios, waiting for tree to go green)

21304 Implement toString for Images on web (cla: yes, waiting for tree to go green)