REGRESSION(r109729) [Form] Rendering of select/optgroup/option combin…

…ation is too slow.

https://bugs.webkit.org/show_bug.cgi?id=88059

Reviewed by Kent Tamura.

This patch changes to share RenderStyle object among the "option"
elements to improve rendering performance and reducing memory usage
of RenderStyle.

No new tests. This patch doesn't change behavior but rendering performance.

* css/StyleResolver.cpp:
(WebCore::StyleResolver::canShareStyleWithElement): Check attribute value
mismatching for "option" element.


Canonical link: https://commits.webkit.org/105892@main
git-svn-id: https://svn.webkit.org/repository/webkit/trunk@119213 268f45cc-cd09-0410-ab3c-d52691b4dbfc

Source/WebCore/ChangeLog

@@ -1,3 +1,20 @@
+2012-06-01  Yoshifumi Inoue  <yosin@chromium.org>
+
+        REGRESSION(r109729) [Form] Rendering of select/optgroup/option combination is too slow.
+        https://bugs.webkit.org/show_bug.cgi?id=88059
+
+        Reviewed by Kent Tamura.
+
+        This patch changes to share RenderStyle object among the "option" 
+        elements to improve rendering performance and reducing memory usage
+        of RenderStyle.
+
+        No new tests. This patch doesn't change behavior but rendering performance.
+
+        * css/StyleResolver.cpp:
+        (WebCore::StyleResolver::canShareStyleWithElement): Check attribute value
+        mismatching for "option" element.
+
 2012-06-01  Alexander Pavlov  <apavlov@chromium.org>
 
         Web Inspector: [REGRESSION] Bad layout of "Override device metrics" controls in the Settings dialog

Source/WebCore/css/StyleResolver.cpp

@@ -1389,8 +1389,14 @@ bool StyleResolver::canShareStyleWithElement(StyledElement* element) const
     }
 #endif
 
-    if (element->hasTagName(optionTag))
-        return false;
+    // Check attributes for :disabled, :enabeld, :checked, :default, CSS pseudo class.
+    if (element->hasTagName(optionTag)) {
+        HTMLOptionElement* thisOptionElement = toHTMLOptionElement(element);
+        HTMLOptionElement* otherOptionElement = toHTMLOptionElement(m_element);
+        if (thisOptionElement->isEnabledFormControl() != otherOptionElement->isEnabledFormControl()
+            || thisOptionElement->selected() != otherOptionElement->selected())
+            return false;
+    }
 
     if (element->hasTagName(optgroupTag) && m_element->disabled() != element->disabled())
         return false;