Bind the workspace synchronously if started on -1 screen.

Previously, LoaderTask would be run asynchronously to bind
the workspace when started on -1 which would cause the user's
wallpaper to briefly flash when rotating the device on -1.

Bug: 11802691
Change-Id: I3a1a7a32fa28a81e041a283a93d808d5a8884133
diff --git a/src/com/android/launcher3/Launcher.java b/src/com/android/launcher3/Launcher.java
index e2301ba..9aaee5a 100644
--- a/src/com/android/launcher3/Launcher.java
+++ b/src/com/android/launcher3/Launcher.java
@@ -456,7 +456,7 @@
             if (DISABLE_SYNCHRONOUS_BINDING_CURRENT_PAGE || sPausedFromUserAction) {
                 // If the user leaves launcher, then we should just load items asynchronously when
                 // they return.
-                mModel.startLoader(true, -1);
+                mModel.startLoader(true, PagedView.INVALID_RESTORE_PAGE);
             } else {
                 // We only load the page synchronously if the user rotates (or triggers a
                 // configuration change) while launcher is in the foreground
@@ -914,7 +914,7 @@
         sPausedFromUserAction = false;
         if (mRestoring || mOnResumeNeedsLoad) {
             mWorkspaceLoading = true;
-            mModel.startLoader(true, -1);
+            mModel.startLoader(true, PagedView.INVALID_RESTORE_PAGE);
             mRestoring = false;
             mOnResumeNeedsLoad = false;
         }