Roll forward up to cl/355302206.

cpp/platform/api/BUILD

@@ -53,6 +53,7 @@ cc_library(
     deps = [
         "//proto/connections:offline_wire_formats_portable_proto",
         "//platform/base",
+        "//platform/base:cancellation_flag",
         "//absl/strings",
         "//absl/types:optional",
         "//webrtc/api:libjingle_peerconnection_api",

cpp/platform/api/ble.h

@@ -3,6 +3,7 @@
 
 #include "platform/api/bluetooth_classic.h"
 #include "platform/base/byte_array.h"
+#include "platform/base/cancellation_flag.h"
 #include "platform/base/input_stream.h"
 #include "platform/base/output_stream.h"
 
@@ -98,8 +99,9 @@ class BleMedium {
   // Connects to a BLE peripheral.
   // On success, returns a new BleSocket.
   // On error, returns nullptr.
-  virtual std::unique_ptr<BleSocket> Connect(BlePeripheral& peripheral,
-                                             const std::string& service_id) = 0;
+  virtual std::unique_ptr<BleSocket> Connect(
+      BlePeripheral& peripheral, const std::string& service_id,
+      CancellationFlag* cancellation_flag) = 0;
 };
 
 }  // namespace api

cpp/platform/api/bluetooth_classic.h

@@ -5,6 +5,7 @@
 #include <string>
 
 #include "platform/base/byte_array.h"
+#include "platform/base/cancellation_flag.h"
 #include "platform/base/exception.h"
 #include "platform/base/input_stream.h"
 #include "platform/base/listeners.h"
@@ -122,7 +123,8 @@ class BluetoothClassicMedium {
   // On success, returns a new BluetoothSocket.
   // On error, returns nullptr.
   virtual std::unique_ptr<BluetoothSocket> ConnectToService(
-      BluetoothDevice& remote_device, const std::string& service_uuid) = 0;
+      BluetoothDevice& remote_device, const std::string& service_uuid,
+      CancellationFlag* cancellation_flag) = 0;
 
   // https://developer.android.com/reference/android/bluetooth/BluetoothAdapter.html#listenUsingInsecureRfcommWithServiceRecord
   //

cpp/platform/api/wifi_lan.h

@@ -4,6 +4,7 @@
 #include <string>
 
 #include "platform/base/byte_array.h"
+#include "platform/base/cancellation_flag.h"
 #include "platform/base/input_stream.h"
 #include "platform/base/listeners.h"
 #include "platform/base/nsd_service_info.h"
@@ -99,7 +100,8 @@ class WifiLanMedium {
   // On success, returns a new WifiLanSocket.
   // On error, returns nullptr.
   virtual std::unique_ptr<WifiLanSocket> Connect(
-      WifiLanService& wifi_lan_service, const std::string& service_id) = 0;
+      WifiLanService& wifi_lan_service, const std::string& service_id,
+      CancellationFlag* cancellation_flag) = 0;
 
   virtual WifiLanService* GetRemoteService(const std::string& ip_address,
                                            int port) = 0;