Re-apply "Adding a mechanism to 'upgrade' the Dart type of elements"

Re-apply "Adding a mechanism to 'upgrade' the Dart type of elements"

With fixes for:
- Expected analyzer static error in the unittest.
- Added browser/interop.js to the HTML file


BUG=
R=jmesserly@google.com

Committed: https://code.google.com/p/dart/source/detail?r=35080

[blois, 2014-04-15 19:29:11]

https://codereview.chromium.org/224113003/diff/1/tests/html/custom/element_up...
File tests/html/custom/element_upgrade_test.html (right):

https://codereview.chromium.org/224113003/diff/1/tests/html/custom/element_up...
tests/html/custom/element_upgrade_test.html:49:
src="/packages/browser/interop.js"></script>
Added interop.js

https://codereview.chromium.org/224113003/diff/1/tests/html/html.status
File tests/html/html.status (right):

https://codereview.chromium.org/224113003/diff/1/tests/html/html.status#newco...
tests/html/html.status:442: custom/element_upgrade_test: StaticWarning
Added.

https://codereview.chromium.org/224113003/diff/1/tools/dom/templates/html/imp...
File tools/dom/templates/html/impl/impl_HTMLDocument.darttemplate (right):

https://codereview.chromium.org/224113003/diff/1/tools/dom/templates/html/imp...
tools/dom/templates/html/impl/impl_HTMLDocument.darttemplate:318: abstract class
ElementUpgrader {
Avoiding Dartium perf regression by moving this class out of this part.

[Jennifer Messerly, 2014-04-15 19:34:43]

lgtm!

https://codereview.chromium.org/224113003/diff/1/tests/html/html.status
File tests/html/html.status (right):

https://codereview.chromium.org/224113003/diff/1/tests/html/html.status#newco...
tests/html/html.status:442: custom/element_upgrade_test: StaticWarning
On 2014/04/15 19:29:12, blois wrote:
> Added.

just curious, what's the warning about?

[blois, 2014-04-15 20:47:43]

https://codereview.chromium.org/224113003/diff/1/tests/html/html.status
File tests/html/html.status (right):

https://codereview.chromium.org/224113003/diff/1/tests/html/html.status#newco...
tests/html/html.status:442: custom/element_upgrade_test: StaticWarning
On 2014/04/15 19:34:43, John Messerly wrote:
> On 2014/04/15 19:29:12, blois wrote:
> > Added.
> 
> just curious, what's the warning about?

Warning is that a class which says it implements HtmlElement does not have all
of the members. The class in question is to make sure that only classes which
subclass HtmlElement can be upgraded and I did not want to implement every
member (would be fragile).

[blois, 2014-04-15 20:50:55]

Committed patchset #2 manually as r35080 (presubmit successful).