Define a set of methods on Launcher which can be safely called externally

-> The methods are defined by an interface, LauncherExterns, which Launcher
   implements

Change-Id: I61362761f5d90fbc3011ce000944768d5ab29d43
diff --git a/src/com/android/launcher3/Launcher.java b/src/com/android/launcher3/Launcher.java
index 4e379a1..51df013 100644
--- a/src/com/android/launcher3/Launcher.java
+++ b/src/com/android/launcher3/Launcher.java
@@ -136,8 +136,8 @@
  * Default launcher application.
  */
 public class Launcher extends Activity
-        implements View.OnClickListener, OnLongClickListener, LauncherModel.Callbacks,
-                   View.OnTouchListener, LauncherProviderChangeListener,
+        implements LauncherExterns, View.OnClickListener, OnLongClickListener,
+                   LauncherModel.Callbacks, View.OnTouchListener, LauncherProviderChangeListener,
                    AccessibilityManager.AccessibilityStateChangeListener {
     public static final String TAG = "Launcher";
     static final boolean LOGD = false;
@@ -1842,7 +1842,7 @@
         return mModel;
     }
 
-    protected SharedPreferences getSharedPrefs() {
+    public SharedPreferences getSharedPrefs() {
         return mSharedPrefs;
     }
 
diff --git a/src/com/android/launcher3/LauncherCallbacks.java b/src/com/android/launcher3/LauncherCallbacks.java
index 89eef60..34117b6 100644
--- a/src/com/android/launcher3/LauncherCallbacks.java
+++ b/src/com/android/launcher3/LauncherCallbacks.java
@@ -1,3 +1,19 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 package com.android.launcher3;
 
 import android.content.Intent;
diff --git a/src/com/android/launcher3/LauncherExterns.java b/src/com/android/launcher3/LauncherExterns.java
new file mode 100644
index 0000000..c7a8668
--- /dev/null
+++ b/src/com/android/launcher3/LauncherExterns.java
@@ -0,0 +1,32 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.launcher3;
+
+import android.content.SharedPreferences;
+
+/**
+ * This interface defines the set of methods that the Launcher activity exposes. Methods
+ * here should be safe to call from classes outside of com.android.launcher3.*
+ */
+public interface LauncherExterns {
+
+    public boolean setLauncherCallbacks(LauncherCallbacks callbacks);
+
+    public SharedPreferences getSharedPrefs();
+
+    public void setLauncherOverlay(Launcher.LauncherOverlay overlay);
+}