Fix for bug 6110465.

Add layout bound metadata to 9-patch files and make layouts take them into account.

This CL contains a proposed API for dealing with layout bounds.

This solution exposes:

1. Class: Insets - for storing layout Insets (and later possibly padding).
2. Methods: View:(get/set)LayoutInsets() - for storing layoutBounds.
3. Methods: ViewGroup:(get/set)LayoutMode() - for controlling layoutMode.

It also iuncudes the changes to GridLayout to support layout bounds.

Change-Id: I60c836b6530b61c5abf37f93ee9c44aad73573f1