Adding A feature flag to disable widgets  and a corresponding build
target Launcher3Go without widgets support

Bug: 62353159
Change-Id: Ia03d2235a9bcf75f9ef191924f81630e63a2c684
diff --git a/src/com/android/launcher3/LauncherProvider.java b/src/com/android/launcher3/LauncherProvider.java
index 4813571..dc83f36 100644
--- a/src/com/android/launcher3/LauncherProvider.java
+++ b/src/com/android/launcher3/LauncherProvider.java
@@ -1031,7 +1031,7 @@
         }
 
         public AppWidgetHost newLauncherWidgetHost() {
-            return new AppWidgetHost(mContext, Launcher.APPWIDGET_HOST_ID);
+            return new LauncherAppWidgetHost(mContext);
         }
 
         @Override