Roll forward up to cl/351408510.

cpp/core/internal/mediums/bluetooth_classic.cc

@@ -332,6 +332,18 @@ bool BluetoothClassic::StopAcceptingConnections(
 
 BluetoothSocket BluetoothClassic::Connect(BluetoothDevice& bluetooth_device,
                                           const std::string& service_name) {
+  for (int attempts_count = 0; attempts_count < kConnectAttemptsLimit;
+       attempts_count++) {
+    auto wrapper_result = AttemptToConnect(bluetooth_device, service_name);
+    if (wrapper_result.IsValid()) {
+      return wrapper_result;
+    }
+  }
+  return BluetoothSocket();
+}
+
+BluetoothSocket BluetoothClassic::AttemptToConnect(
+    BluetoothDevice& bluetooth_device, const std::string& service_name) {
   MutexLock lock(&mutex_);
   NEARBY_LOG(INFO, "BluetoothClassic::Connect: device=%p", &bluetooth_device);
   // Socket to return. To allow for NRVO to work, it has to be a single object.

cpp/core/internal/mediums/bluetooth_classic.h

@@ -91,8 +91,8 @@ class BluetoothClassic {
     return adapter_.IsValid();
   }
 
-  // Establishes connection to BT service that was might be started on another
-  // device with StartAcceptingConnections() using the same service_name.
+  // Establishes connection to BT service with internal retry for maximum
+  // attempts of kConnectAttemptsLimit.
   // Blocks until connection is established, or server-side is terminated.
   // Returns socket instance. On success, BluetoothSocket.IsValid() return true.
   // Called by client.
@@ -112,6 +112,8 @@ class BluetoothClassic {
 
   static constexpr int kMaxConcurrentAcceptLoops = 5;
 
+  static constexpr int kConnectAttemptsLimit = 3;
+
   // Constructs UUID object from arbitrary string, using MD5 hash, and then
   // converts UUID to a readable UUID string and returns it.
   static std::string GenerateUuidFromString(const std::string& data);
@@ -146,6 +148,14 @@ class BluetoothClassic {
   // Returns true if device is currently in discovery mode.
   bool IsDiscovering() const ABSL_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
 
+  // Establishes connection to BT service that was might be started on another
+  // device with StartAcceptingConnections() using the same service_name.
+  // Blocks until connection is established, or server-side is terminated.
+  // Returns socket instance. On success, BluetoothSocket.IsValid() return true.
+  // Called by client.
+  BluetoothSocket AttemptToConnect(BluetoothDevice& bluetooth_device,
+                                   const std::string& service_name);
+
   mutable Mutex mutex_;
   BluetoothRadio& radio_ ABSL_GUARDED_BY(mutex_);
   BluetoothAdapter& adapter_ ABSL_GUARDED_BY(mutex_){