<http://webkit.org/b/74991>

Reviewed by Antti Koivisto.

Remove caching of the "id" and "name" attributes on applet, embed, form,
image and object elements. We were caching them to keep the document's
map of named and "extra named" (named by id) item counts in sync.

Instead, add a hook to Element::willModifyAttribute() that detects when
the attributes are being changed and handle the registration/unregistration
automatically if the element returns true for shouldRegisterAsNamedItem()
or shouldRegisterAsExtraNamedItem() respectively.

This shrinks the elements by two AtomicStrings (8 or 16 bytes) each.

IFrame elements retain the old mechanism for now, as there are some subtle
differences to how that's handled.

* dom/Node.h:
(WebCore::Node::hasName):
(WebCore::Node::setHasName):

    Cache whether we have a "name" attribute or not (1 bit on Node.)
    This is done in order to minimize the overhead added to Element's
    insertedIntoDocument() and removeFromDocument().

* dom/Element.cpp:
(WebCore::Element::updateNamedItemRegistration):
(WebCore::Element::updateExtraNamedItemRegistration):

    Added. Called when the "name" and "id" attributes are changed.
    Updates the document's named item maps accordingly.

(WebCore::Element::insertedIntoDocument):
(WebCore::Element::removedFromDocument):

    Make sure updateName() is called in addition to updateId() when applicable.

(WebCore::Element::attributeChanged):

    Update the Node's has-name flag as appropriate.

* dom/Element.h:
(WebCore::Element::shouldRegisterAsNamedItem):
(WebCore::Element::shouldRegisterAsExtraNamedItem):

    Added. If an element returns true for these, it will be automatically
    registered with the document when the name/id attribute changes.

(WebCore::Element::updateId):
(WebCore::Element::updateName):

    Register/unregister from the document's named item maps as appropriate.

(WebCore::Element::willModifyAttribute):

    Add updateName() hook in addition to the existing updateId() hook.

* dom/NamedNodeMap.cpp:
(WebCore::NamedNodeMap::setAttributes):

    Make sure updateName() is called when we're cloning the attributes
    from another element.

* html/HTMLAppletElement.cpp:
(WebCore::HTMLAppletElement::parseMappedAttribute):
* html/HTMLAppletElement.h:
* html/HTMLEmbedElement.cpp:
(WebCore::HTMLEmbedElement::parseMappedAttribute):
(WebCore::HTMLEmbedElement::insertedIntoDocument):
* html/HTMLEmbedElement.h:
* html/HTMLFormElement.cpp:
(WebCore::HTMLFormElement::insertedIntoDocument):
(WebCore::HTMLFormElement::removedFromDocument):
(WebCore::HTMLFormElement::parseMappedAttribute):
* html/HTMLFormElement.h:
* html/HTMLImageElement.cpp:
(WebCore::HTMLImageElement::parseMappedAttribute):
(WebCore::HTMLImageElement::insertedIntoDocument):
* html/HTMLImageElement.h:
* html/HTMLObjectElement.cpp:
(WebCore::HTMLObjectElement::parseMappedAttribute):
(WebCore::HTMLObjectElement::insertedIntoDocument):
(WebCore::HTMLObjectElement::removedFromDocument):
* html/HTMLObjectElement.h:
* html/HTMLPlugInElement.h:

    Remove duplicated code that is now handled by Element.

* html/HTMLObjectElement.cpp:
(WebCore::HTMLObjectElement::updateDocNamedItem):
(WebCore::HTMLObjectElement::formControlName):

    Use fastGetAttribute() since we no longer cache the name.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@103473 268f45cc-cd09-0410-ab3c-d52691b4dbfc