bluetooth: Return int8_t and use -128 for unknown tx power.

device/bluetooth/bluetooth_classic_device_mac.mm

Index: device/bluetooth/bluetooth_classic_device_mac.mm
diff --git a/device/bluetooth/bluetooth_classic_device_mac.mm b/device/bluetooth/bluetooth_classic_device_mac.mm
index 985596ecfc59873e8797f52d9690489597abda9c..f2f3ffaa76c6a5ba2162d774e8a0c9f059894a56 100644
--- a/device/bluetooth/bluetooth_classic_device_mac.mm
+++ b/device/bluetooth/bluetooth_classic_device_mac.mm
@@ -145,13 +145,13 @@ BluetoothDevice::UUIDList BluetoothClassicDeviceMac::GetUUIDs() const {
   return uuids;
 }
 
-int16_t BluetoothClassicDeviceMac::GetInquiryRSSI() const {
-  return kUnknownPower;
+base::Optional<int8_t> BluetoothClassicDeviceMac::GetInquiryRSSI() const {
+  return base::Optional<int8_t>();

[scheib, 2016/05/07 02:06:52]

return nullopt;

 }
 
-int16_t BluetoothClassicDeviceMac::GetInquiryTxPower() const {
+base::Optional<int8_t> BluetoothClassicDeviceMac::GetInquiryTxPower() const {
   NOTIMPLEMENTED();
-  return kUnknownPower;
+  return base::Optional<int8_t>();
 }
 
 bool BluetoothClassicDeviceMac::ExpectingPinCode() const {
@@ -177,11 +177,12 @@ void BluetoothClassicDeviceMac::GetConnectionInfo(
     return;
   }
 
-  connection_info.rssi = [device_ rawRSSI];
+  BluetoothHCIRSSIValue rssi = [device_ rawRSSI];
+
   // The API guarantees that +127 is returned in case the RSSI is not readable:
   // http://goo.gl/bpURYv
-  if (connection_info.rssi == 127)
-    connection_info.rssi = kUnknownPower;
+  if (rssi == 127)
+    connection_info.rssi = base::make_optional(rssi);

[scheib, 2016/05/07 02:06:52]

In the event rssi is 127 we want to use nullopt, else make_optional(rssi); I
think:
  connection_info.rssi = (rssi == 127) ? base::nullopt :
base::make_optional(rssi);

 
   connection_info.transmit_power =
       GetHostTransmitPower(kReadCurrentTransmitPowerLevel);
@@ -256,7 +257,7 @@ NSDate* BluetoothClassicDeviceMac::GetLastUpdateTime() const {
   return [device_ getLastInquiryUpdate];
 }
 
-int BluetoothClassicDeviceMac::GetHostTransmitPower(
+base::Optional<int8_t> BluetoothClassicDeviceMac::GetHostTransmitPower(
     BluetoothHCITransmitPowerLevelType power_level_type) const {
   IOBluetoothHostController* controller =
       [IOBluetoothHostController defaultController];
@@ -266,7 +267,7 @@ int BluetoothClassicDeviceMac::GetHostTransmitPower(
                                                        inType:
                                         outTransmitPowerLevel:);
   if (![controller respondsToSelector:selector])
-    return kUnknownPower;
+    return base::nullopt;
 
   BluetoothHCITransmitPowerLevel power_level;
   IOReturn result =
@@ -274,9 +275,9 @@ int BluetoothClassicDeviceMac::GetHostTransmitPower(
                                               inType:power_level_type
                                outTransmitPowerLevel:&power_level];
   if (result != kIOReturnSuccess)
-    return kUnknownPower;
+    return base::nullopt;
 
-  return power_level;
+  return base::make_optional(power_level);
 }
 
 // static