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

chrome/android/java/strings/android_chrome_strings.grd

Index: chrome/android/java/strings/android_chrome_strings.grd
diff --git a/chrome/android/java/strings/android_chrome_strings.grd b/chrome/android/java/strings/android_chrome_strings.grd
index fd69f79a157fe0b8043ca9a00534c62d91cdb3ee..65a0a8ccc869b1448abbacb83d366a8bcb47e9aa 100644
--- a/chrome/android/java/strings/android_chrome_strings.grd
+++ b/chrome/android/java/strings/android_chrome_strings.grd
@@ -1192,7 +1192,13 @@ To obtain new licenses, connect to the internet and play your downloaded content
         <ph name="BEGIN_LINK">&lt;link&gt;</ph>Help<ph name="END_LINK">&lt;/link&gt;</ph>
       </message>
       <message name="IDS_BLUETOOTH_NEED_LOCATION_PERMISSION" desc="The message to show when scanning cannot start because Chrome needs the Location permission in order for Android to return any Bluetooth devices from a scan.">
-        Chrome needs location access to scan for devices. <ph name="BEGIN_LINK">&lt;link&gt;</ph>Update permissions<ph name="END_LINK">&lt;/link&gt;</ph>
+        Chrome needs location access to scan for devices. <ph name="BEGIN_LINK">&lt;permission_link&gt;</ph>Update permissions<ph name="END_LINK">&lt;/permission_link&gt;</ph>
+      </message>
+      <message name="IDS_BLUETOOTH_NEED_LOCATION_SERVICES_ON" desc="The message to show when scanning cannot start because Android location services are off, but they must be turned on for Android to return any Bluetooth devices from a scan.">

[scheib, 2016/06/03 20:48:29]

I left string thoughts on
https://bugs.chromium.org/p/chromium/issues/detail?id=545867

[Jeffrey Yasskin, 2016/06/06 16:16:56]

I've updated the strings to roughly Rebecca's suggestions, and will wait for her
to approve them on the bug.

+        Chrome needs location services to be turned on to scan for devices. <ph name="BEGIN_LINK">&lt;services_link&gt;</ph>Turn them on<ph name="END_LINK">&lt;/services_link&gt;</ph>
+      </message>
+      <message name="IDS_BLUETOOTH_NEED_LOCATION_PERMISSION_AND_SERVICES_ON" desc="The message to show when scanning cannot start because Chrome doesn't have the Location permission and the device's location services are turned off, and both must be enabled in order for Android to return any Bluetooth devices from a scan.">
+        Chrome needs location access to scan for devices. <ph name="BEGIN_LINK1">&lt;permission_link&gt;</ph>Update permissions<ph name="END_LINK1">&lt;/permission_link&gt;</ph>  <ph name="BEGIN_LINK2">&lt;services_link&gt;</ph>Turn on location services<ph name="END_LINK2">&lt;/services_link&gt;</ph>
       </message>
       <message name="IDS_BLUETOOTH_NEED_LOCATION_PERMISSION_HELP" desc="The status message to get more information about why Chrome needs the Location permission in order to scan for Bluetooth devices.">
         <ph name="BEGIN_LINK">&lt;link&gt;</ph>Help<ph name="END_LINK">&lt;/link&gt;</ph>