Refactoring: Decouple ScriptElement from HTMLScriptElement and SVGScriptElement.

Refactoring: Decouple ScriptElement from HTMLScriptElement and SVGScriptElement.

This change pulls ScriptElement out from Element inheritance chain.
This give us an opportunity to decouple the lifetime of the element and
script loading and execution. Various states which is realted to script loading
won't be needed and can be discarded once it is feed to the script engine.
Such refactoring will follow.

Also in a coming change, ScriptElement will be renamed to ElementScriptLoader.

TEST=none
BUG=240592
R=eseidel,dglazkov,abarth

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=153748

[Hajime Morrita, 2013-07-04 08:22:15]

Refactoring for HTML Imports continues...

For coming changes, I'd like to 
- Morph ScriptElement into ElementScriptLoader
- Makes it a RefCounted and unify to PendingScript

This decoupling helps, because HTML Imports is going to run <script>
from other document in the "master", active document. 
It's confusing to move ScriptElement across document.

[abarth-chromium, 2013-07-08 18:42:00]

realted -> related

[abarth-chromium, 2013-07-08 18:47:12]

LGTM

This CL leaves the code in a confusing state.  Please rename ScriptElement
soon!!!  :)

Rather than ElementScriptLoader, maybe ScriptLoader would be a good name?  Also,
I didn't see any reason why you needed to handle the m_scriptElement being zero
case.  If possible, it would be nice to make the code assume that
m_scriptElement is always non-zero.

https://codereview.chromium.org/18676002/diff/3002/Source/core/html/HTMLScrip...
File Source/core/html/HTMLScriptElement.cpp (right):

https://codereview.chromium.org/18676002/diff/3002/Source/core/html/HTMLScrip...
Source/core/html/HTMLScriptElement.cpp:59: if (m_scriptElement)
When would m_scriptElement ever be zero?

https://codereview.chromium.org/18676002/diff/3002/Source/core/svg/SVGScriptE...
File Source/core/svg/SVGScriptElement.h (right):

https://codereview.chromium.org/18676002/diff/3002/Source/core/svg/SVGScriptE...
Source/core/svg/SVGScriptElement.h:80: virtual bool haveFiredLoadEvent() const {
return m_scriptElement->haveFiredLoadEvent(); }
I would move these into the CPP file.

[commit-bot: I haz the power, 2013-07-09 00:05:23]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/morrita@chromium.org/18676002/3002

[Hajime Morrita, 2013-07-09 00:06:44]

Thanks for the review!

> Rather than ElementScriptLoader, maybe ScriptLoader would be a good name? 
Also,
> I didn't see any reason why you needed to handle the m_scriptElement being
zero
> case.  If possible, it would be nice to make the code assume that
> m_scriptElement is always non-zero.

My overall plan is to delete the instance once the script is evaluated.
But yes, the check should be added on that timing. Will remove the check before
landing.

[commit-bot: I haz the power, 2013-07-09 00:37:37]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/morrita@chromium.org/18676002/7002

[commit-bot: I haz the power, 2013-07-09 05:39:19]

Change committed as 153748