Nested scrolling: android-support-v4 edition

Implement the nested scrolling patterns from Android 5.0 Lollipop for
use on older platform versions.

Custom nested scrolling child views should implement the new interface
NestedScrollingChild. These views can instantiate a
NestedScrollingChildHelper and delegate overridden interface and
View/ViewGroup methods to the helper methods of the same name. The
helper will manage associated state and behavior.

Similarly, custom nested scrolling ViewGroups should implement
NestedScrollingParent and create a NestedScrollingParentHelper,
delegating methods of the same name to the helper.

Nested scrolling methods should be invoked via the
ViewCompat/ViewParentCompat shims. These shims will delegate to the
proper implementation for both framework and support views that allow
nested scrolling.

Now with bonus NestedScrollView!

Bug 18195379

Change-Id: Ia125816875a9caf19baab545a65b9404240c8d8b
13 files changed