16624 update hash code logic on the web (cla: yes)

16625 [web] Paragraph.getBoxesForRange uses LineMetrics (affects: text input, cla: yes, platform-web)

16626 [web] Skipping failing edge tests (cla: yes)

16628 Roll src/third_party/dart edd64e6d5c79..11ae06e988de (44 commits) (cla: yes, waiting for tree to go green)

16629 Kick LUCI (cla: yes)

16630 URL-encode asset URLs so assets are properly loaded (cla: yes)