Refactor the layout for MasterSwitch to a 2 target pref

And move the layout to settingslib.

The new TwoTargetPreference is a preference object that has a vertical
divider between main panel and widget (if it exists).

Converted master switch, restricted preference, gear preference to use
the new style

Change-Id: Ia3848cebb06b8edc4e60abf9b0caf13cdb29c22c
Fix: 36511169
Test: make RunSettingsRoboTests

src/com/android/settings/widget/GearPreference.java

@@ -33,7 +33,6 @@ public class GearPreference extends RestrictedPreference implements View.OnClick
 
     public GearPreference(Context context, AttributeSet attrs) {
         super(context, attrs);
-        setWidgetLayoutResource(R.layout.preference_widget_settings);
     }
 
     public void setOnGearClickListener(OnGearClickListener l) {
@@ -41,6 +40,16 @@ public class GearPreference extends RestrictedPreference implements View.OnClick
         notifyChanged();
     }
 
+    @Override
+    protected int getSecondTargetResId() {
+        return R.layout.preference_widget_gear;
+    }
+
+    @Override
+    protected boolean shouldHideSecondTarget() {
+        return mOnGearClickListener == null;
+    }
+
     @Override
     public void onBindViewHolder(PreferenceViewHolder holder) {
         super.onBindViewHolder(holder);