[Nearby] Use SharedRemote in Bluetooth Socket

Previously, the socket's remote was bound on a different thread from
the one that would eventually call Disconnect which was causing a
deadlock when Nearby Connections was cleaning up a channel.

By switching to a shared remote that is explicitly bound on the task
runner we avoid the deadlock with minimal changes.

Fixed: 1132738
Change-Id: I19f89d5f38cc6ae88237038aa3cc0cc6e3eb8f5b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2437689
Auto-Submit: James Vecore <vecore@google.com>
Reviewed-by: Ryan Hansberry <hansberry@chromium.org>
Commit-Queue: James Vecore <vecore@google.com>
Cr-Commit-Position: refs/heads/master@{#812255}

chrome/services/sharing/nearby/platform_v2/bluetooth_socket.cc

@@ -257,8 +257,9 @@ BluetoothSocket::BluetoothSocket(
     mojo::ScopedDataPipeProducerHandle send_stream)
     : remote_device_(std::move(device)),
       remote_device_ref_(*remote_device_),
-      task_runner_(base::ThreadPool::CreateSequencedTaskRunner({})),
-      socket_(std::move(socket)) {
+      task_runner_(
+          base::ThreadPool::CreateSequencedTaskRunner({base::MayBlock()})),
+      socket_(std::move(socket), task_runner_) {
   InitializeStreams(std::move(receive_stream), std::move(send_stream));
 }
 
@@ -268,8 +269,9 @@ BluetoothSocket::BluetoothSocket(
     mojo::ScopedDataPipeConsumerHandle receive_stream,
     mojo::ScopedDataPipeProducerHandle send_stream)
     : remote_device_ref_(remote_device),
-      task_runner_(base::ThreadPool::CreateSequencedTaskRunner({})),
-      socket_(std::move(socket)) {
+      task_runner_(
+          base::ThreadPool::CreateSequencedTaskRunner({base::MayBlock()})),
+      socket_(std::move(socket), task_runner_) {
   InitializeStreams(std::move(receive_stream), std::move(send_stream));
 }
 

chrome/services/sharing/nearby/platform_v2/bluetooth_socket.h

@@ -10,7 +10,7 @@
 #include "base/optional.h"
 #include "chrome/services/sharing/nearby/platform_v2/bluetooth_device.h"
 #include "device/bluetooth/public/mojom/adapter.mojom.h"
-#include "mojo/public/cpp/bindings/remote.h"
+#include "mojo/public/cpp/bindings/shared_remote.h"
 #include "third_party/nearby/src/cpp/platform_v2/api/bluetooth_classic.h"
 #include "third_party/nearby/src/cpp/platform_v2/base/input_stream.h"
 #include "third_party/nearby/src/cpp/platform_v2/base/output_stream.h"
@@ -105,7 +105,7 @@ class BluetoothSocket : public api::BluetoothSocket {
   scoped_refptr<base::SequencedTaskRunner> task_runner_;
 
   // These properties must be created on |task_runner_|. See |task_runner_|.
-  mojo::Remote<bluetooth::mojom::Socket> socket_;
+  mojo::SharedRemote<bluetooth::mojom::Socket> socket_;
   std::unique_ptr<InputStream> input_stream_;
   std::unique_ptr<OutputStream> output_stream_;
 };