9561 libtxt: fix reference counting of SkFontStyleSets held by font asset providers (cla: yes)

9562 Switched preprocessor logic for exporting symbols for testing. (cla: yes)

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

9584 Revert “ Roll src/third_party/dart b37aa3b036…1eb113ba27” (cla: yes)

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

9588 Roll src/third_party/dart b37aa3b036…0abff7b2bb (cla: yes)

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