Settings - update for new UI (no more Drawer)

- follow the UX spec by no more using a Drawer
- the Dashboard is now a Fragment that contains the list of Headers
- the search results are also put into a Fragment that is replacing
the initial one (Dashboard or other) when expanding the SearchView
- use a SearchView for query input
- when tapping on a Header or a Search Result, re-launch Settings as
an Activity so that we are benefiting from the Activity stack for
UP affordance and BACK button
- manage UP affordance to show it only when needed
- move some Actions to the Menu in the ActionBar for allowing space
to the Search action and removing some clutter
- fix an issue with the Index and WiFiEnabler and their cached Context
that was not updated when there was a Configuration change
- simplify the SettingsActivity code by extracting some inner classes

Change-Id: I50b5f77bb44a7fade1886114dbbc820609a5e63d

src/com/android/settings/wifi/WifiEnabler.java

@@ -38,7 +38,7 @@ import com.android.settings.search.Index;
 import java.util.concurrent.atomic.AtomicBoolean;
 
 public class WifiEnabler implements CompoundButton.OnCheckedChangeListener  {
-    private final Context mContext;
+    private Context mContext;
     private Switch mSwitch;
     private AtomicBoolean mConnected = new AtomicBoolean(false);
 
@@ -77,7 +77,8 @@ public class WifiEnabler implements CompoundButton.OnCheckedChangeListener  {
         mIntentFilter.addAction(WifiManager.NETWORK_STATE_CHANGED_ACTION);
     }
 
-    public void resume() {
+    public void resume(Context context) {
+        mContext = context;
         // Wi-Fi state is sticky, so just let the receiver update UI
         mContext.registerReceiver(mReceiver, mIntentFilter);
         mSwitch.setOnCheckedChangeListener(this);