Add in a new FrameConsumer interface, Decode API, and a RectangleUpdateDecoder abstraction.

This should allow a decoder that can still request the view to allocate frames without being owned by the view itself.  This allows for cleaner threading semantics and reduced coupling of classes.  The new decoder API keeps the decoder from being aware of the network packet types tightening up the API layering.

BUG=52833
TEST=None. This code isn't used yet.

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=60703

Review URL: http://codereview.chromium.org/3335012

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@60721 0039d316-1c4b-4281-b951-d872f2087c98