message: Updates some comments.
diff: @@ -234,12 +234,12 @@ class AsyncOpKernel : public OpKernel {
  // Implementations of ComputeAsync() must ensure that `done` is (eventually)
  // called exactly once to signal the completion of the computation. The
  // implementation of ComputeAsync() must not block on the execution of another
  - // OpKernel. `done` may be called by the current thread, or by another thread
  + // OpKernel. `done` may be called by the current thread, or by another thread.
  // `context` is guaranteed to stay alive until the `done` callback starts.
  //
  // Since it is possible that the unblocking kernel may never run (due to an
  // error or cancellation), in most cases the AsyncOpKernel should implement
  - // cancellation support via `ctx->cancellation_manager()`.
  + // cancellation support via `context->cancellation_manager()`.
  //
  // WARNING: As soon as the `done` callback starts, `context` and `this` may be
  // deleted. No code depending on these objects should execute after the call
  @@ -253,12 +253,11 @@ class AsyncOpKernel : public OpKernel {
  void Compute(OpKernelContext* context) final;
  };
  -// Wraps a tensor that is held by an Op across calls to Compute(). For
  -// memory safety when using asynchronous devices like GPUs, the system
  -// must be notified when a Tensor is used inside an Op execution. The
  -// wrapper ensures that all uses of the Tensor are tracked, because in
  -// order to retrieve the Tensor the caller must use AccessTensor which
  -// notifies the context.
  +// Wraps a tensor that is held by an Op across calls to Compute(). For memory
  +// safety when using asynchronous devices like GPUs, the system must be notified
  +// when a Tensor is used inside an Op execution. The wrapper ensures that all
  +// uses of the Tensor are tracked, because in order to retrieve the Tensor the
  +// caller must use AccessTensor which notifies the context.
  class PersistentTensor {
  public:
  PersistentTensor() {}
  