Sky: different tack for custom Rect type in the Canvas API.

Sky: different tack for custom Rect type in the Canvas API.

Rect is now a dart-only type, defined in its own .dart file. I use
DartConverter when passing a Rect into C++. I also special-cased Rect in the
IDL compiler so that it's passed by value, instead of allocating a new
Rect object on the heap.

This also adds a mechanism to add custom .dart files to dart_sky.dart - used by
Rect.dart.

R=eseidel@chromium.org

Committed: https://chromium.googlesource.com/external/mojo/+/35734ee34225770865be6e5bbe1a2476299333de

[Matt Perry, 2015-05-20 19:12:52]

mpcomplete@chromium.org changed reviewers:
+ eseidel@chromium.org

[abarth-chromium, 2015-05-20 19:51:05]

abarth@chromium.org changed reviewers:
+ abarth@chromium.org

[abarth-chromium, 2015-05-20 19:51:06]

Would it be better to use
https://api.dartlang.org/apidocs/channels/stable/dartdoc-viewer/dart:typed_da...
as the internal representation of the Rect?

[abarth-chromium, 2015-05-20 19:52:26]

Then you could use Dart_TypedDataAcquireData to get at the data faster.

[eseidel, 2015-05-20 20:31:11]

lgtm modulo abarth's question.

[Matt Perry, 2015-05-20 20:55:40]

On 2015/05/20 19:52:26, abarth wrote:
> Then you could use Dart_TypedDataAcquireData to get at the data faster.

Cool, thanks for the tip. I ended up using Float32List instead of Float32x4,
because

(1) The latter is not a TypedData, so Dart_TypedDataAcquireData doesn't work.
(2) The former is mutable, which I think we'll want Rect to be (though it
currently isn't).

[Matt Perry, 2015-05-20 21:58:41]

Committed patchset #3 (id:40001) manually as
35734ee34225770865be6e5bbe1a2476299333de (presubmit successful).