If location services are turned off, have the BT chooser prompt the user to turn them on.

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

Index: device/bluetooth/android/java/src/org/chromium/device/bluetooth/ChromeBluetoothAdapter.java
diff --git a/device/bluetooth/android/java/src/org/chromium/device/bluetooth/ChromeBluetoothAdapter.java b/device/bluetooth/android/java/src/org/chromium/device/bluetooth/ChromeBluetoothAdapter.java
index a7751f75fab24955e4642b3ad2cca6efb4924bbe..b298f74f81b909dbe176b4b5262c9b1c337151f8 100644
--- a/device/bluetooth/android/java/src/org/chromium/device/bluetooth/ChromeBluetoothAdapter.java
+++ b/device/bluetooth/android/java/src/org/chromium/device/bluetooth/ChromeBluetoothAdapter.java
@@ -12,6 +12,7 @@ import android.content.BroadcastReceiver;
 import android.content.Context;
 import android.content.Intent;
 import android.content.IntentFilter;
+import android.location.LocationManager;
 import android.os.Build;
 import android.os.ParcelUuid;
 
@@ -186,12 +187,20 @@ final class ChromeBluetoothAdapter extends BroadcastReceiver {
     // Implementation details:
 
     /**
-     * @return true if Chromium has permission to scan for Bluetooth devices.
+     * @return true if Chromium has permission to scan for Bluetooth devices and location services
+     * are on.
      */
     private boolean canScan() {
         Wrappers.ContextWrapper context = mAdapter.getContext();
-        return context.checkPermission(Manifest.permission.ACCESS_COARSE_LOCATION)
+        boolean havePermission = context.checkPermission(Manifest.permission.ACCESS_COARSE_LOCATION)
                 || context.checkPermission(Manifest.permission.ACCESS_FINE_LOCATION);
+
+        Wrappers.LocationManagerWrapper locationManager = context.getLocationManager();
+        boolean locationServicesOn =
+                locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER)

[Jeffrey Yasskin, 2016/06/03 01:52:48]

https://developer.android.com/reference/android/location/LocationManager.html...
recommends using Settings.Secure.getInt(LOCATION_MODE), but Chrome has 3 uses of
isProviderEnabled() vs 1 use of getInt(LOCATION_MODE). Which should we be using
in general?

+                || locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER);
+
+        return havePermission && locationServicesOn;
     }
 
     private void registerBroadcastReceiver() {