17421 Roll src/third_party/dart 11d6bc605512..e8c4aed700f5 (20 commits) (cla: yes, waiting for tree to go green)

17423 [fuchsia] Remove “CreateTraceProvider” trace event (cla: yes)

17425 Strengthen json string comparisons (cla: yes)

17426 Implement getExtractedText in InputConnectionAdaptor (affects: text input, cla: yes, platform-android, waiting for tree to go green)

17428 GPU to raster rename, patch 2 (cla: yes, waiting for tree to go green)

17429 Fix iOS builds on Xcode 11.4 for new enum values added in iOS 13.4. (cla: yes)

17431 Use Metal on iOS by default. (cla: yes)