Handle createShadowSubtree inside of ensureUserAgentShadowRoot
https://bugs.webkit.org/show_bug.cgi?id=108116

Reviewed by Dimitri Glazkov.

Instead of making everyone create the UserAgentShadowRoot manually all
over, centralize it in ensureUserAgentShadowRoot() and add a notification
Element::didAddUserAgentShadowRoot that lets elements fill in the subtree.
This lets us get rid of lots of code duplication.

No new tests, just refactoring.

* dom/Element.cpp:
(WebCore::Element::ensureUserAgentShadowRoot):
* dom/Element.h:
(WebCore::Element::didAddUserAgentShadowRoot):
(Element):
* html/HTMLDetailsElement.cpp:
(WebCore::DetailsSummaryElement::create):
(WebCore::HTMLDetailsElement::create):
(WebCore::HTMLDetailsElement::didAddUserAgentShadowRoot):
* html/HTMLDetailsElement.h:
(HTMLDetailsElement):
* html/HTMLInputElement.cpp:
(WebCore::HTMLInputElement::create):
(WebCore::HTMLInputElement::didAddUserAgentShadowRoot):
* html/HTMLInputElement.h:
(HTMLInputElement):
* html/HTMLMediaElement.cpp:
(WebCore::HTMLMediaElement::willAddAuthorShadowRoot):
(WebCore::HTMLMediaElement::createMediaControls):
* html/HTMLMediaElement.h:
* html/HTMLMeterElement.cpp:
(WebCore::HTMLMeterElement::create):
(WebCore::HTMLMeterElement::didAddUserAgentShadowRoot):
* html/HTMLMeterElement.h:
(HTMLMeterElement):
* html/HTMLProgressElement.cpp:
(WebCore::HTMLProgressElement::create):
(WebCore::HTMLProgressElement::didAddUserAgentShadowRoot):
* html/HTMLProgressElement.h:
* html/HTMLSummaryElement.cpp:
(WebCore::HTMLSummaryElement::create):
(WebCore::HTMLSummaryElement::didAddUserAgentShadowRoot):
* html/HTMLSummaryElement.h:
(HTMLSummaryElement):
* html/HTMLTextAreaElement.cpp:
(WebCore::HTMLTextAreaElement::create):
(WebCore::HTMLTextAreaElement::didAddUserAgentShadowRoot):
* html/HTMLTextAreaElement.h:
* html/shadow/MediaControlElements.cpp:
(WebCore::MediaControlPanelMuteButtonElement::create):
(WebCore::MediaControlVolumeSliderMuteButtonElement::create):
(WebCore::MediaControlPlayButtonElement::create):
(WebCore::MediaControlOverlayPlayButtonElement::create):
(WebCore::MediaControlSeekForwardButtonElement::create):
(WebCore::MediaControlSeekBackButtonElement::create):
(WebCore::MediaControlRewindButtonElement::create):
(WebCore::MediaControlReturnToRealtimeButtonElement::create):
(WebCore::MediaControlToggleClosedCaptionsButtonElement::create):
(WebCore::MediaControlTimelineElement::create):
(WebCore::MediaControlPanelVolumeSliderElement::create):
(WebCore::MediaControlFullscreenVolumeSliderElement::create):
(WebCore::MediaControlFullscreenButtonElement::create):
(WebCore::MediaControlFullscreenVolumeMinButtonElement::create):
(WebCore::MediaControlFullscreenVolumeMaxButtonElement::create):
* html/shadow/MediaControlsBlackBerry.cpp:
(WebCore::MediaControlFullscreenPlayButtonElement::create):
(WebCore::MediaControlFullscreenFullscreenButtonElement::create):
(WebCore::MediaControlFullscreenTimelineElement::create):
(WebCore::MediaControlAudioMuteButtonElement::create):
* svg/SVGTRefElement.cpp:
(WebCore::SVGTRefElement::create):
* svg/SVGTRefElement.h:
(SVGTRefElement):
* svg/SVGUseElement.cpp:
(WebCore::SVGUseElement::create):
* svg/SVGUseElement.h:
(SVGUseElement):


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@141066 268f45cc-cd09-0410-ab3c-d52691b4dbfc
diff --git a/Source/WebCore/html/HTMLMeterElement.cpp b/Source/WebCore/html/HTMLMeterElement.cpp
index 465d0ff..3918331 100644
--- a/Source/WebCore/html/HTMLMeterElement.cpp
+++ b/Source/WebCore/html/HTMLMeterElement.cpp
@@ -54,7 +54,7 @@
 PassRefPtr<HTMLMeterElement> HTMLMeterElement::create(const QualifiedName& tagName, Document* document)
 {
     RefPtr<HTMLMeterElement> meter = adoptRef(new HTMLMeterElement(tagName, document));
-    meter->createShadowSubtree();
+    meter->ensureUserAgentShadowRoot();
     return meter;
 }
 
@@ -234,11 +234,9 @@
     return static_cast<RenderMeter*>(renderObject);
 }
 
-void HTMLMeterElement::createShadowSubtree()
+void HTMLMeterElement::didAddUserAgentShadowRoot(ShadowRoot* root)
 {
-    ASSERT(!userAgentShadowRoot());
-           
-    RefPtr<ShadowRoot> root = ShadowRoot::create(this, ShadowRoot::UserAgentShadowRoot, ASSERT_NO_EXCEPTION);
+    ASSERT(!m_value);
 
     RefPtr<MeterInnerElement> inner = MeterInnerElement::create(document());
     root->appendChild(inner);