Homescreen migration from a larger grid to a smaller grid.

Adding support for restoring from a larger device, if the grid size
difference is not more that 1.
During restore add all the items in the DB, and run a one-time migration
the next time launcher starts.

The migration strategy is defined in ShrinkWorkspaceTask.java which involves
resizing, moving and removing some items.

Change-Id: I6ee411f6db5bf0152b527e16146a88c56dec2d97
diff --git a/src/com/android/launcher3/LauncherAppState.java b/src/com/android/launcher3/LauncherAppState.java
index 0b7b1fd..ecaf801 100644
--- a/src/com/android/launcher3/LauncherAppState.java
+++ b/src/com/android/launcher3/LauncherAppState.java
@@ -17,7 +17,6 @@
 package com.android.launcher3;
 
 import android.app.SearchManager;
-import android.content.ComponentName;
 import android.content.Context;
 import android.content.Intent;
 import android.content.IntentFilter;
@@ -147,7 +146,7 @@
         sLauncherProvider = new WeakReference<LauncherProvider>(provider);
     }
 
-    static LauncherProvider getLauncherProvider() {
+    public static LauncherProvider getLauncherProvider() {
         return sLauncherProvider.get();
     }