Add a basic sky-element custom element

Add a basic sky-element custom element

After this CL, you can use <sky-element> to describe custom elements. The
current iteration is very basic and is hardcoded to "example", but its a start.

This CL renames the |init| function to |_init| to prevent importers from
calling it directly. Also, we now pass the <script> element to |_init| to give
some context.

R=ojan@chromium.org, eseidel@chromium.org

Committed: https://chromium.googlesource.com/external/mojo/+/8cc5e112ccc4741f8c25c46a3d94f963314957cf

[eseidel, 2015-02-21 00:08:13]

We talked about _init being needed on the main sky as well.

https://codereview.chromium.org/950493003/diff/1/sky/engine/core/html/parser/...
File sky/engine/core/html/parser/HTMLScriptRunner.cpp (right):

https://codereview.chromium.org/950493003/diff/1/sky/engine/core/html/parser/...
sky/engine/core/html/parser/HTMLScriptRunner.cpp:119:
frame->dart().ExecuteLibraryInModule(module.get(),
We should just pass the script and hang the library off hte script.

[ojan, 2015-02-21 00:19:15]

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

[ojan, 2015-02-21 00:19:16]

https://codereview.chromium.org/950493003/diff/1/sky/examples/example-element...
File sky/examples/example-element/example-element.sky (right):

https://codereview.chromium.org/950493003/diff/1/sky/examples/example-element...
sky/examples/example-element/example-element.sky:20: class ExampleElement
extends SkyElement {
Not directly related to this patch, but how hard would it be to have the tag
name be the class name? IMO, we should consider the implications of that.
Obviously that shouldn't block this patch though.

[abarth-chromium, 2015-02-21 00:25:57]

https://codereview.chromium.org/950493003/diff/1/sky/examples/example-element...
File sky/examples/example-element/example-element.sky (right):

https://codereview.chromium.org/950493003/diff/1/sky/examples/example-element...
sky/examples/example-element/example-element.sky:20: class ExampleElement
extends SkyElement {
On 2015/02/21 at 00:19:16, ojan wrote:
> Not directly related to this patch, but how hard would it be to have the tag
name be the class name? IMO, we should consider the implications of that.
Obviously that shouldn't block this patch though.

Very easy.  In fact, it would be less code than we have currently.

[ojan, 2015-02-21 01:44:38]

lgtm

[abarth-chromium, 2015-02-21 05:40:05]

https://codereview.chromium.org/950493003/diff/1/sky/engine/core/html/parser/...
File sky/engine/core/html/parser/HTMLScriptRunner.cpp (right):

https://codereview.chromium.org/950493003/diff/1/sky/engine/core/html/parser/...
sky/engine/core/html/parser/HTMLScriptRunner.cpp:119:
frame->dart().ExecuteLibraryInModule(module.get(),
On 2015/02/21 at 00:08:13, eseidel wrote:
> We should just pass the script and hang the library off hte script.

Ok.  I'll do this in a later CL.

[abarth-chromium, 2015-02-21 05:45:41]

Committed patchset #1 (id:1) manually as
8cc5e112ccc4741f8c25c46a3d94f963314957cf (presubmit successful).