Fix lock level violations when dumping low overhead traces

There were two lock level violations in the code that dumps low overhead
traces
1. We should not wait for checkpoints to finish while holding the
   trace_lock_. This CL fixes it by waiting for the checkpoints after
   releasing the trace_lock_. Since we release trace_lock_ while waiting
   we need additional synchronization to make sure trace_data_ isn't
   deleted while checkpoints are still running. This is done using a
   ConditionVariable and waiting on it if a trace dump is in progress
   before deleting the trace_data_.
2. We should not enter a ScopedObjectAccess (that acquires mutator lock)
   while holding the bottom level trace_data_lock_. We now take a
   snapshot of the traced_methods and traced_threads when holding the
   trace_data_lock_ and then dump thread and method information outside
   the lock. Dumping methods requires mutator lock to get the
   information about the method.

Bug: 352518093
Test: Manual testing with feature enabled and kDebugLocking enabled.

Change-Id: I42a61f4d43eb985a93bc7884c09f771a5fbcd8f2

0 files changed, 0 insertions, 0 deletions