[DO NOT MERGE] Changing WallpaperChangeReceiver to a runtime registered broadcast receiver

Bug: 28115607
Change-Id: I208d629a346781d9b1fbeb0a245685bf36f85aeb
(cherry picked from commit d435cc070a)

AndroidManifest.xml

@@ -127,13 +127,6 @@
             android:process=":settings_process">
         </activity>
 
-        <receiver
-            android:name="com.android.launcher3.WallpaperChangedReceiver">
-            <intent-filter>
-                <action android:name="android.intent.action.WALLPAPER_CHANGED" />
-            </intent-filter>
-        </receiver>
-
         <!-- Intent received used to install shortcuts from other applications -->
         <receiver
             android:name="com.android.launcher3.InstallShortcutReceiver"

src/com/android/launcher3/LauncherAppState.java

@@ -106,6 +106,9 @@ public class LauncherAppState {
         sContext.registerReceiver(mModel, filter);
         UserManagerCompat.getInstance(sContext).enableAndResetCache();
         new ConfigMonitor(sContext).register();
+
+        sContext.registerReceiver(
+                new WallpaperChangedReceiver(), new IntentFilter(Intent.ACTION_WALLPAPER_CHANGED));
     }
 
     /**