20922 Increase thread priority before engine init (cla: yes, perf: speed, platform-android, severe: performance)

20931 Clear the GL context only after submitting the frame (cla: yes)

20932 Log the results when ShellTest.Screenshot fails (cla: yes, waiting for tree to go green)

20935 Log exception in addition to the stack trace for unhandled exceptions. (cla: yes)

20936 Revert “Adds fuchsia node roles to accessibility bridge updates.” (cla: yes)

20937 Revert “Create root isolate asynchronously” (cla: yes, waiting for tree to go green)

20950 Revert external size changes to Picture (cla: yes)

20953 restore FML_DCHECK removed due to a code reviewing error (cla: yes)