12821 Update buildroot to pull in ubsan updates. (cla: yes)

12931 remove references to package:_chrome (cla: yes)

12958 Adding deviceId to KeyEventChannel enconding method (cla: yes)

12960 Fix typo on channel buffer debug output. (cla: yes)

12972 Re-land Adding Link Semantics (accessibility, affects: framework, cla: yes)

12974 Support empty strings and vectors in standard codec (cla: yes)

12977 Unblock Fuchsia roll (cla: yes)

12980 Made _printDebug only happen on debug builds of the engine for now. (cla: yes)

12982 Color matrix doc (cla: yes)