partition_alloc: copy PlatformThread to PA library.

Split PlatformThread into (1) PlatformThread and
(2) PlatformThreadForTesting.
(1) is the code PartitionAlloc really depends on. (2) is the code
PartitionAlloc tests depend on. For example, PlatformThread::Join() is
used by thread_cache_unittests, but PartitionAlloc library doesn't use
it.

PS1 = just copying platform_thread* to PA library

Bug: 1151236
Change-Id: Ibce58993c15155b9f521a181b75e93e6daa14c66
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3612910
Reviewed-by: Yuki Shiino <yukishiino@chromium.org>
Reviewed-by: Bartek Nowierski <bartekn@chromium.org>
Commit-Queue: Takashi Sakamoto <tasak@google.com>
Cr-Commit-Position: refs/heads/main@{#1003104}
NOKEYCHECK=True
GitOrigin-RevId: 2fa10639fd51d4f1aac5d616db91d43493449cb5
1 file changed
tree: 42c14811adcbb2168e8a35ea0396b047e1277b53
  1. asan/
  2. partition_allocator/
  3. tsan_v2/
  4. OWNERS