Fix PrioritizedSerialExecutor.

It was possible that fetchNextTasks() would be called by multiple
threads concurrently.
If it happens, some tasks in the task queues might be ignored.

Change-Id: Idc81c43c45e382da3850cc55b9a42c281548d2a8
4 files changed
tree: c9d3fff6dfe6c3fa23d68cc99a4fcb70847a7ef3
  1. dictionaries/
  2. java/
  3. native/
  4. tests/
  5. tools/
  6. Android.mk
  7. CleanSpec.mk