VCD: Fix comment in CameraHalDispatcherImpl::RegisterClient

Fixes the comments written in CameraHalDispatcherImpl::RegisterClient.

Bug: b/173577612
Test: Build simplechrome
Change-Id: I2ab5ec0ed36f54b8441befe9e218c8acac35aca8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2546392
Auto-Submit: Jasmine Chen <lnishan@google.com>
Commit-Queue: Ricky Liang <jcliang@chromium.org>
Reviewed-by: Ricky Liang <jcliang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#829095}

media/capture/video/chromeos/camera_hal_dispatcher_impl.cc

@@ -232,9 +232,8 @@ void CameraHalDispatcherImpl::RegisterServerWithToken(
 
 void CameraHalDispatcherImpl::RegisterClient(
     mojo::PendingRemote<cros::mojom::CameraHalClient> client) {
-  // RegisterClient can be called locally by ArcCameraBridge. Unretained
-  // reference is safe here because CameraHalDispatcherImpl owns
-  // |proxy_thread_|.
+  // RegisterClient can be called locally by ArcCameraBridge, so it's not
+  // necessarily called on |proxy_thread_|.
 
   // TODO(b/170075468): Reject this call once we've migrated all camera clients.
   auto temporary_token = base::UnguessableToken::Create();
@@ -249,6 +248,8 @@ void CameraHalDispatcherImpl::RegisterClientWithToken(
     const base::UnguessableToken& auth_token,
     RegisterClientWithTokenCallback callback) {
   base::UnguessableToken client_auth_token = auth_token;
+  // Unretained reference is safe here because CameraHalDispatcherImpl owns
+  // |proxy_thread_|.
   proxy_task_runner_->PostTask(
       FROM_HERE,
       base::BindOnce(