Adds basic touch handling to sprites and optimizes transformations

Optimizes sprite transformations for box to node
Enabling/disabling of handling multiple pointers
Adds basic touch handling

R=abarth@chromium.org

Committed: https://chromium.googlesource.com/external/mojo/+/c4add9bd5b19f161c53a747b9993e947b3f9995e

[viktorl, 2015-06-18 21:04:53]

viktorl@google.com changed reviewers:
+ abarth@chromium.org

[abarth-chromium, 2015-06-18 21:19:21]

lgtm

https://codereview.chromium.org/1179413009/diff/1/sky/examples/game/lib/sprit...
File sky/examples/game/lib/sprite_box.dart (right):

https://codereview.chromium.org/1179413009/diff/1/sky/examples/game/lib/sprit...
sky/examples/game/lib/sprite_box.dart:104: if (node.hitTest(posInNodeSpace)) {
Do you want to move this work into the |hitTest| function on this object?  It's
strange to perform hit testing during |handleEvent| instead of during |hitTest|.

[viktorl, 2015-06-18 22:29:31]

Committed patchset #1 (id:1) manually as
c4add9bd5b19f161c53a747b9993e947b3f9995e (presubmit successful).