9806 Reuse texture cache in ios_external_texture_gl. (cla: yes)

9864 Add capability to add AppDelegate as UNUserNotificationCenterDelegate (cla: yes)

9888 Provide dart vm initalize isolate callback so that children isolates belong to parent’s isolate group. (cla: yes)

10154 Started taking advantage of Skia’s new copyTableData to avoid superfluous copies. (cla: yes)

10182 Made flutter startup faster by allowing initialization to be parallelized (cla: yes)

10326 copypixelbuffer causes crash (cla: yes)

10670 Expose LineMetrics in dart:ui (affects: text input, brand new feature, cla: yes)

10814 Reland remove kernel sdk script (cla: yes, platform-web)