Refactor Bluetooth settings for readability and performance.

Major refactoring of Bluetooth settings classes.
- Moved all functionality from LocalBluetoothManager into new
  LocalBluetoothAdapter and LocalBluetoothPreferences, and into
  existing classes.
- Refactored functionality from BluetoothEventRedirector into new
  BluetoothEventManager class, deleting the original version. New
  version uses a HashMap from action Strings to implementers of the
  BluetoothEventManager.Handler interface.
- Created new BluetoothDiscoveryReceiver to update shared preferences
  timestamp for Bluetooth discovery start/finish. This is the only event
  handling we need to do when the settings app is not visible, so it has
  its own receiver entry in AndroidManifest.xml. Edits are written using
  QueuedWork.singleThreadExecutor(), which BroadcastReceiver knows about
  and will wait for completion, eliminating the need for PendingResult.
- Miscellaneous cleanups to code style and logic for readability.
- Pulled some large switch statement code blocks into new methods.
- Changed all Bluetooth state references to the new BluetoothProfile
  constants.
- Changed use of deprecated Notification constructor in
  BluetoothPairingRequest to use Notification.Builder.
- Moved Utf8ByteLengthFilter helper function from BluetoothNamePreference
  into its own class, and moved test cases into the same package.
- Moved all LocalBluetoothProfileManager functionality related to
  specific profiles into new top-level classes (A2dpProfile, etc.), all
  implementing the LocalBluetoothProfile interface.
- Moved all UI-related methods from CachedBluetoothDevice into the class
  that uses the method, or into the static Utils class for shared methods.

Change-Id: I6d49b7f4ae0c7d7dcf62551ee40b51ecb5fe4f47

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

@@ -34,13 +34,14 @@ import android.widget.Toast;
  * preference. It turns on/off Bluetooth and ensures the summary of the
  * preference reflects the current state.
  */
-public class BluetoothEnabler implements Preference.OnPreferenceChangeListener {
+public final class BluetoothEnabler implements Preference.OnPreferenceChangeListener {
     private final Context mContext;
     private final CheckBoxPreference mCheckBox;
     private final CharSequence mOriginalSummary;
 
-    private final LocalBluetoothManager mLocalManager;
+    private final LocalBluetoothAdapter mLocalAdapter;
     private final IntentFilter mIntentFilter;
+
     private final BroadcastReceiver mReceiver = new BroadcastReceiver() {
         @Override
         public void onReceive(Context context, Intent intent) {
@@ -49,14 +50,15 @@ public class BluetoothEnabler implements Preference.OnPreferenceChangeListener {
         }
     };
 
-    public BluetoothEnabler(Context context, CheckBoxPreference checkBox) {
+    public BluetoothEnabler(Context context, LocalBluetoothAdapter adapter,
+            CheckBoxPreference checkBox) {
         mContext = context;
         mCheckBox = checkBox;
         mOriginalSummary = checkBox.getSummary();
         checkBox.setPersistent(false);
 
-        mLocalManager = LocalBluetoothManager.getInstance(context);
-        if (mLocalManager == null) {
+        mLocalAdapter = adapter;
+        if (adapter == null) {
             // Bluetooth is not supported
             checkBox.setEnabled(false);
         }
@@ -64,19 +66,19 @@ public class BluetoothEnabler implements Preference.OnPreferenceChangeListener {
     }
 
     public void resume() {
-        if (mLocalManager == null) {
+        if (mLocalAdapter == null) {
             return;
         }
 
         // Bluetooth state is not sticky, so set it manually
-        handleStateChanged(mLocalManager.getBluetoothState());
+        handleStateChanged(mLocalAdapter.getBluetoothState());
 
         mContext.registerReceiver(mReceiver, mIntentFilter);
         mCheckBox.setOnPreferenceChangeListener(this);
     }
 
     public void pause() {
-        if (mLocalManager == null) {
+        if (mLocalAdapter == null) {
             return;
         }
 
@@ -95,14 +97,14 @@ public class BluetoothEnabler implements Preference.OnPreferenceChangeListener {
             return false;
         }
 
-        mLocalManager.setBluetoothEnabled(enable);
+        mLocalAdapter.setBluetoothEnabled(enable);
         mCheckBox.setEnabled(false);
 
         // Don't update UI to opposite state until we're sure
         return false;
     }
 
-    /* package */ void handleStateChanged(int state) {
+    void handleStateChanged(int state) {
         switch (state) {
             case BluetoothAdapter.STATE_TURNING_ON:
                 mCheckBox.setSummary(R.string.wifi_starting);