9581 Revert “Avoid a full screen overlay within virtual displays” (cla: yes)

9585 Fix a race in the embedder accessibility unit test (cla: yes)

9589 Fixes a plugin overwrite bug in the plugin shim system. (cla: yes)

9590 Apply patches that have landed in topaz since we ported the runners to the engine repo (cla: yes)

9591 Document various classes in //flutter/shell/common. (cla: yes)

9593 [trace clients] Remove fuchsia.tracelink.Registry (cla: yes)

9608 Disable failing Mutators tests (cla: yes)

9613 Fix uninitialized variables and put tests in flutter namespace. (cla: yes)

9632 Added Doxyfile. (cla: yes)