https://bugs.webkit.org/show_bug.cgi?id=90866

Reviewed by Hajime Morita.

It ensures that UserAgentShadowDOM is the oldest ShadowDOM.

To show ValidationMessage, WebKit adds a Shadow DOM to some of FormControlElements.
ValidationMessage assumes that the added Shadow DOM is the oldest, however, there was a case
that a page author might add a Shadow DOM before ValidationMessage adds a Shadow DOM.
It will break the assumption that the Shadow DOM added by ValidationMessage is the oldest.
So we have prohibited a page author adding a Shadow DOM to FormControlElement.

To add UserAgentShadowDOM, we use a callback which is called before a page author adding a Shadow DOM.
It adds a UserAgentShadowDOM if it does not exist, so we can ensure that UserAgentShadowDOM is the oldest.

Tests: fast/dom/shadow/input-with-validation-without-shadow.html
       fast/dom/shadow/input-with-validation.html
       fast/dom/shadow/shadowdom-for-button-complex-shadow.html
       fast/dom/shadow/shadowdom-for-button-only-shadow.html
       fast/dom/shadow/shadowdom-for-button-without-shadow.html
       fast/dom/shadow/shadowdom-for-fieldset-complex-shadow.html
       fast/dom/shadow/shadowdom-for-fieldset-only-shadow.html
       fast/dom/shadow/shadowdom-for-fieldset-without-shadow.html
       fast/dom/shadow/shadowdom-for-form-associated-element-useragent.html
       fast/dom/shadow/shadowdom-for-keygen-complex-shadow.html
       fast/dom/shadow/shadowdom-for-keygen-only-shadow.html
       fast/dom/shadow/shadowdom-for-keygen-without-shadow.html
       fast/dom/shadow/shadowdom-for-object-complex-shadow.html
       fast/dom/shadow/shadowdom-for-object-only-shadow.html
       fast/dom/shadow/shadowdom-for-object-without-shadow.html
       fast/dom/shadow/shadowdom-for-output-complex-shadow.html
       fast/dom/shadow/shadowdom-for-output-only-shadow.html
       fast/dom/shadow/shadowdom-for-output-without-shadow.html
       fast/dom/shadow/shadowdom-for-select-complex-shadow.html
       fast/dom/shadow/shadowdom-for-select-only-shadow.html
       fast/dom/shadow/shadowdom-for-select-without-shadow.html
       fast/dom/shadow/shadowdom-for-textarea-complex-shadow.html
       fast/dom/shadow/shadowdom-for-textarea-only-shadow.html
       fast/dom/shadow/shadowdom-for-textarea-without-shadow.html

* dom/ShadowRoot.cpp:
(WebCore::allowsAuthorShadowRoot):
* html/FormAssociatedElement.cpp:
(WebCore::FormAssociatedElement::ensureUserAgentShadowRoot): Ensures the existence of a UserAgentShadowRoot.
If it does not exist, we create it with empty content.
(WebCore):
* html/FormAssociatedElement.h:
(FormAssociatedElement):
* html/HTMLFormControlElement.cpp:
(WebCore::HTMLFormControlElement::willAddAuthorShadowRoot):
(WebCore):
* html/HTMLFormControlElement.h:
(HTMLFormControlElement):
* html/ValidationMessage.cpp:
(WebCore::adjustBubblePosition): When AuthroShadowRoot does not a shadow element, ValidationMessage
does not have a renderer. So we have to check the existence of renderer.
(WebCore::ValidationMessage::buildBubbleTree):

LayoutTests: Add UserAgentShadowDOM to FormControlElement just before ading UserShadowDOM
https://bugs.webkit.org/show_bug.cgi?id=90866

Reviewed by Hajime Morita.

Added a lot of tests of ShadowDOM for replaced elements. They don't crash,
but many of them are not rendered correctly. Please see Bug 82313,
which is a meta bug of Shadow DOM for replaced elements.

* fast/dom/shadow/input-with-validation-expected.html: Added.
* fast/dom/shadow/input-with-validation-without-shadow-expected.html: Added.
* fast/dom/shadow/input-with-validation-without-shadow.html: Added.
* fast/dom/shadow/input-with-validation.html: Added.
* fast/dom/shadow/shadow-disable-expected.txt:
* fast/dom/shadow/shadow-disable.html:
* fast/dom/shadow/shadowdom-for-button-complex-shadow-expected.html: Added.
* fast/dom/shadow/shadowdom-for-button-complex-shadow.html: Added.
* fast/dom/shadow/shadowdom-for-button-only-shadow-expected.html: Added.
* fast/dom/shadow/shadowdom-for-button-only-shadow.html: Added.
* fast/dom/shadow/shadowdom-for-button-without-shadow-expected.html: Added.
* fast/dom/shadow/shadowdom-for-button-without-shadow.html: Added.
* fast/dom/shadow/shadowdom-for-fieldset-complex-shadow-expected.html: Added.
* fast/dom/shadow/shadowdom-for-fieldset-complex-shadow.html: Added.
* fast/dom/shadow/shadowdom-for-fieldset-only-shadow-expected.html: Added.
* fast/dom/shadow/shadowdom-for-fieldset-only-shadow.html: Added.
* fast/dom/shadow/shadowdom-for-fieldset-without-shadow-expected.html: Added.
* fast/dom/shadow/shadowdom-for-fieldset-without-shadow.html: Added.
* fast/dom/shadow/shadowdom-for-form-associated-element-useragent-expected.txt: Added.
* fast/dom/shadow/shadowdom-for-form-associated-element-useragent.html: Added.
* fast/dom/shadow/shadowdom-for-keygen-complex-shadow-expected.html: Added.
* fast/dom/shadow/shadowdom-for-keygen-complex-shadow.html: Added.
* fast/dom/shadow/shadowdom-for-keygen-only-shadow-expected.html: Added.
* fast/dom/shadow/shadowdom-for-keygen-only-shadow.html: Added.
* fast/dom/shadow/shadowdom-for-keygen-without-shadow-expected.html: Added.
* fast/dom/shadow/shadowdom-for-keygen-without-shadow.html: Added.
* fast/dom/shadow/shadowdom-for-object-complex-shadow-expected.html: Added.
* fast/dom/shadow/shadowdom-for-object-complex-shadow.html: Added.
* fast/dom/shadow/shadowdom-for-object-only-shadow-expected.html: Added.
* fast/dom/shadow/shadowdom-for-object-only-shadow.html: Added.
* fast/dom/shadow/shadowdom-for-object-without-shadow-expected.html: Added.
* fast/dom/shadow/shadowdom-for-object-without-shadow.html: Added.
* fast/dom/shadow/shadowdom-for-output-complex-shadow-expected.html: Added.
* fast/dom/shadow/shadowdom-for-output-complex-shadow.html: Added.
* fast/dom/shadow/shadowdom-for-output-only-shadow-expected.html: Added.
* fast/dom/shadow/shadowdom-for-output-only-shadow.html: Added.
* fast/dom/shadow/shadowdom-for-output-without-shadow-expected.html: Added.
* fast/dom/shadow/shadowdom-for-output-without-shadow.html: Added.
* fast/dom/shadow/shadowdom-for-select-complex-shadow-expected.html: Added.
* fast/dom/shadow/shadowdom-for-select-complex-shadow.html: Added.
* fast/dom/shadow/shadowdom-for-select-only-shadow-expected.html: Added.
* fast/dom/shadow/shadowdom-for-select-only-shadow.html: Added.
* fast/dom/shadow/shadowdom-for-select-without-shadow-expected.html: Added.
* fast/dom/shadow/shadowdom-for-select-without-shadow.html: Added.
* fast/dom/shadow/shadowdom-for-textarea-complex-shadow-expected.html: Added.
* fast/dom/shadow/shadowdom-for-textarea-complex-shadow.html: Added.
* fast/dom/shadow/shadowdom-for-textarea-only-shadow-expected.html: Added.
* fast/dom/shadow/shadowdom-for-textarea-only-shadow.html: Added.
* fast/dom/shadow/shadowdom-for-textarea-without-shadow-expected.html: Added.
* fast/dom/shadow/shadowdom-for-textarea-without-shadow.html: Added.
* platform/chromium/TestExpectations:
* platform/efl/TestExpectations:
* platform/qt/Skipped:
* platform/wincairo/Skipped:


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@123713 268f45cc-cd09-0410-ab3c-d52691b4dbfc