Improve Bluetooth tethering UI usability.

- Updated hint text for BT tethering checkbox to
  "[Sharing|not sharing] this [tablet|phone]'s mobile data connection".
- Show correct hint text when user enters tethering screen.
- Show correct status after user enables tethering when Bluetooth is off.
  When BluetoothPan.setBluetoothTethering(true) is called with BT off,
  BluetoothPanProfileHandler will add a broadcast receiver to enable
  tethering after BT turns on. This happens too late to show the correct
  status when TetherSettings gets the adapter state changed event, so set
  a flag (mBluetoothEnableForTether) instead, and call setBluetoothTethering
  ourselves after the state changes to ON. Also, clear the flag if the
  adapter state changes to OFF or ERROR.
- Show correct status when user enables tethering, then disables Bluetooth,
  then returns to the tethering screen. Previously it would show
  Bluetooth tethering enabled, even though adapter state was OFF.
- Show the number of connected devices in tethering preference screen.
- Distinguish between PANU and NAP in device profiles screen, and show
  appropriate text to clarify the direction of tethering.
- Remove profiles from device profiles list when the device removes the UUID
  (e.g. Mac OS X turning NAP on/off) and after a NAP disconnection when the
  remote device only supports PANU.

Bug: 3414575
Change-Id: I2c0830876d5b9bddb293e57c4d3ca74f105911b8

src/com/android/settings/bluetooth/DeviceProfilesSettings.java

@@ -239,7 +239,7 @@ public final class DeviceProfilesSettings extends SettingsPreferenceFragment
         if (TextUtils.isEmpty(name)) {
             name = context.getString(R.string.bluetooth_device);
         }
-        int disconnectMessage = profile.getDisconnectResource();
+        int disconnectMessage = profile.getDisconnectResource(device.getDevice());
         if (disconnectMessage == 0) {
             Log.w(TAG, "askDisconnect: unexpected profile " + profile);
             disconnectMessage = R.string.bluetooth_disconnect_blank;
@@ -288,6 +288,13 @@ public final class DeviceProfilesSettings extends SettingsPreferenceFragment
                 refreshProfilePreference(profilePref, profile);
             }
         }
+        for (LocalBluetoothProfile profile : mCachedDevice.getRemovedProfiles()) {
+            Preference profilePref = findPreference(profile.toString());
+            if (profilePref != null) {
+                Log.d(TAG, "Removing " + profile.toString() + " from profile list");
+                mProfileContainer.removePreference(profilePref);
+            }
+        }
     }
 
     private void refreshProfilePreference(Preference profilePref, LocalBluetoothProfile profile) {