Prevent dragging workspace items to custom content page.

Change-Id: I4279f5feffb9512af66243969efaaadfb9011962
diff --git a/src/com/android/launcher3/Workspace.java b/src/com/android/launcher3/Workspace.java
index edf3721..63211bd 100644
--- a/src/com/android/launcher3/Workspace.java
+++ b/src/com/android/launcher3/Workspace.java
@@ -3698,6 +3698,11 @@
             final int page = getNextPage() +
                        (direction == DragController.SCROLL_LEFT ? -1 : 1);
 
+            // Ensure that we are not dragging over to the custom content screen
+            if (getScreenIdForPageIndex(page) == CUSTOM_CONTENT_SCREEN_ID) {
+                return false;
+            }
+
             // We always want to exit the current layout to ensure parity of enter / exit
             setCurrentDropLayout(null);