During a copy, position:fixed gets converted to position:absolute even if only part...

During a copy, position:fixed gets converted to position:absolute even if only part of the document is selected
https://bugs.webkit.org/show_bug.cgi?id=128688

Reviewed by Ryosuke Niwa.

Source/WebCore:

Adds a field, m_needsPositionStyleConversion, to StyledMarkupAccumulator.

Also, renames the ConvertPositionStyleOnCopy setting to ShouldConvertPositionStyleOnCopy

Test: editing/pasteboard/copy-paste-doesnt-convert-sticky-and-fixed-during-partial-copy.html

* editing/markup.cpp:
(WebCore::StyledMarkupAccumulator::StyledMarkupAccumulator):
(WebCore::StyledMarkupAccumulator::appendElement):
(WebCore::createMarkupInternal):
* page/Settings.in:
* testing/InternalSettings.cpp:
(WebCore::InternalSettings::Backup::Backup):
(WebCore::InternalSettings::Backup::restoreTo):
(WebCore::InternalSettings::setShouldConvertPositionStyleOnCopy):
* testing/InternalSettings.h:
* testing/InternalSettings.idl:

Source/WebKit/mac:

Renames the ConvertPositionStyleOnCopy setting to ShouldConvertPositionStyleOnCopy

* WebView/WebPreferenceKeysPrivate.h:
* WebView/WebPreferences.mm:
(-[WebPreferences shouldConvertPositionStyleOnCopy]):
(-[WebPreferences setShouldConvertPositionStyleOnCopy:]):
* WebView/WebPreferencesPrivate.h:
* WebView/WebView.mm:
(-[WebView _preferencesChanged:]):

Source/WebKit2:

Renames the ConvertPositionStyleOnCopy setting to ShouldConvertPositionStyleOnCopy

* Shared/WebPreferencesStore.h:
* UIProcess/API/C/WKPreferences.cpp:
(WKPreferencesSetShouldConvertPositionStyleOnCopy):
(WKPreferencesGetShouldConvertPositionStyleOnCopy):
* UIProcess/API/C/WKPreferencesPrivate.h:
* WebProcess/WebPage/WebPage.cpp:
(WebKit::WebPage::updatePreferences):

LayoutTests:

Performs a copy of the contents of a particular div, rather than the entire body. Makes sure that
no position:fixed -> position:absolute conversion occurs.

* editing/pasteboard/copy-paste-converts-sticky-and-fixed-expected.txt:
* editing/pasteboard/copy-paste-converts-sticky-and-fixed.html:
* editing/pasteboard/copy-paste-doesnt-convert-sticky-and-fixed-during-partial-copy-expected.txt: Added.
* editing/pasteboard/copy-paste-doesnt-convert-sticky-and-fixed-during-partial-copy.html: Added.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@164053 268f45cc-cd09-0410-ab3c-d52691b4dbfc