bluetooth: Implement simulateGATTConnectionResponse()

device/bluetooth/public/interfaces/test/fake_bluetooth.mojom

Index: device/bluetooth/public/interfaces/test/fake_bluetooth.mojom
diff --git a/device/bluetooth/public/interfaces/test/fake_bluetooth.mojom b/device/bluetooth/public/interfaces/test/fake_bluetooth.mojom
index a9d71faed3b86028292d428c6ecfc4b466a837ec..44017acd1b73d275962a58039775d2afc539329f 100644
--- a/device/bluetooth/public/interfaces/test/fake_bluetooth.mojom
+++ b/device/bluetooth/public/interfaces/test/fake_bluetooth.mojom
@@ -30,6 +30,10 @@ interface FakeBluetooth {
   SimulateCentral(CentralState state) => (FakeCentral fake_central);
 };
 
+// HCI Error Codes from BT 4.2 Vol 2 Part D 1.3 List Of Error Codes.
+const uint16 kHCISuccess = 0x0000;
+const uint16 kHCIConnectionTimeout = 0x0008;
+
 // FakeCentral allows clients to simulate events that a device in the
 // Central/Observer role would receive as well as monitor the operations
 // performed by the device in the Central/Observer role.
@@ -51,4 +55,12 @@ interface FakeCentral {
   SimulatePreconnectedPeripheral(string address,
                                  string name,
                                  array<UUID> known_service_uuids) => ();
+
+  // Simulates a GATT Connection request response with |code| for peripheral
+  // with |address|. |code| could be an HCI Error Code from
+  // BT 4.2 Vol 2 Part D 1.3 List Of Error Codes or a number outside that range
+  // returned by specific platforms e.g. Android returns 0x101 to signal a GATT
+  // failure
+  // https://developer.android.com/reference/android/bluetooth/BluetoothGatt.html#GATT_FAILURE
+  SimulateGATTConnectionResponse(string address, uint16 code) => ();
 };