bluetooth: Increase min api for Android

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

Index: device/bluetooth/android/java/src/org/chromium/device/bluetooth/ChromeBluetoothDevice.java
diff --git a/device/bluetooth/android/java/src/org/chromium/device/bluetooth/ChromeBluetoothDevice.java b/device/bluetooth/android/java/src/org/chromium/device/bluetooth/ChromeBluetoothDevice.java
index 05f4483769eb197a514158640a3b69a6e38e2114..52f1991b480d5490aaf2d526f09ded3bd6849f44 100644
--- a/device/bluetooth/android/java/src/org/chromium/device/bluetooth/ChromeBluetoothDevice.java
+++ b/device/bluetooth/android/java/src/org/chromium/device/bluetooth/ChromeBluetoothDevice.java
@@ -23,7 +23,7 @@ import java.util.HashMap;
  * 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";
 
@@ -108,7 +108,9 @@ final class ChromeBluetoothDevice {
         // 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.