bluetooth: Increase min api for Android

device/bluetooth/android/java/src/org/chromium/device/bluetooth/ChromeBluetoothDevice.java

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.device.bluetooth;
 
 import android.annotation.TargetApi;
 import android.bluetooth.BluetoothDevice;
 import android.content.Context;
 import android.os.Build;
 
 import org.chromium.base.Log;
 import org.chromium.base.annotations.CalledByNative;
 import org.chromium.base.annotations.JNINamespace;
 import org.chromium.base.metrics.RecordHistogram;
 
 import java.util.HashMap;
 
 /**
  * Exposes android.bluetooth.BluetoothDevice as necessary for C++
  * device::BluetoothDeviceAndroid.
  *
  * Lifetime is controlled by device::BluetoothDeviceAndroid.
  */
 @JNINamespace("device")
-@TargetApi(Build.VERSION_CODES.LOLLIPOP)
+@TargetApi(Build.VERSION_CODES.M)
 final class ChromeBluetoothDevice {
     private static final String TAG = "Bluetooth";
 
     private long mNativeBluetoothDeviceAndroid;
     final Wrappers.BluetoothDeviceWrapper mDevice;
     Wrappers.BluetoothGattWrapper mBluetoothGatt;
     private final BluetoothGattCallbackImpl mBluetoothGattCallbackImpl;
     final HashMap<Wrappers.BluetoothGattCharacteristicWrapper,
             ChromeBluetoothRemoteGattCharacteristic> mWrapperToChromeCharacteristicsMap;
     final HashMap<Wrappers.BluetoothGattDescriptorWrapper, ChromeBluetoothRemoteGattDescriptor>
@@ skipping 64 matching lines @@
     // Implements BluetoothDeviceAndroid::CreateGattConnectionImpl.
     @CalledByNative
     private void createGattConnectionImpl(Context context) {
         Log.i(TAG, "connectGatt");
 
         if (mBluetoothGatt != null) mBluetoothGatt.close();
 
         // autoConnect set to false as under experimentation using autoConnect failed to complete
         // connections.
         mBluetoothGatt =
-                mDevice.connectGatt(context, false /* autoConnect */, mBluetoothGattCallbackImpl);
+                mDevice.connectGatt(context, false /* autoConnect */, mBluetoothGattCallbackImpl,
+                        // Prefer LE for dual-mode devices due to lower energy consumption.

[scheib, 2017/04/11 18:08:19]

Let's explain that we don't have any use of Bluetooth classic, the only
bluetooth client on Android so far is GATT for Web Bluetooth. 

[ortuno, 2017/04/11 23:12:47]

I am tad confused here 🤔. What exactly should we comment? This is only about the
preferred transport when establishing a GATT connection. It shouldn't matter
that Web Bluetooth is the only client. Unlike our change to filter out non-LE
devices.

[scheib, 2017/04/12 01:01:54]

Oops, I had forgotten this was just the preferred transport, not a selection of
only doing one kind of transport. Fine as is.

+                        BluetoothDevice.TRANSPORT_LE);
     }
 
     // Implements BluetoothDeviceAndroid::DisconnectGatt.
     @CalledByNative
     private void disconnectGatt() {
         Log.i(TAG, "BluetoothGatt.disconnect");
         if (mBluetoothGatt != null) mBluetoothGatt.disconnect();
     }
 
     // Implements callbacks related to a GATT connection.
@@ skipping 189 matching lines @@
             long nativeBluetoothDeviceAndroid, int status, boolean connected);
 
     // Binds to BluetoothDeviceAndroid::CreateGattRemoteService.
     // TODO(http://crbug.com/505554): Replace 'Object' with specific type when JNI fixed.
     private native void nativeCreateGattRemoteService(long nativeBluetoothDeviceAndroid,
             String instanceId, Object bluetoothGattServiceWrapper);
 
     // Binds to BluetoothDeviceAndroid::GattServicesDiscovered.
     private native void nativeOnGattServicesDiscovered(long nativeBluetoothDeviceAndroid);
 }