26908 [web] Honor background color when rendering text to dom (cla: yes, platform-web)

26909 Reserve space for the line metrics styles created by ParagraphSkia::GetLineMetrics (cla: yes, waiting for tree to go green)

26910 Make clang_tidy test more hermetic (cla: yes)

26915 Roll Dart SDK from 7dcf180a625a to 2ca3cb6a1247 (4 revisions) (cla: yes, waiting for tree to go green)

26916 Symbolize crash backtraces using the Abseil debugging library (cla: yes, waiting for tree to go green)

26917 [web] Librarify keyboard files (cla: yes, platform-web)