Avoid full style rebuild for :-webkit-animating-full-screen-transitio…

…n and :-webkit-full-screen-controls-hidden

https://bugs.webkit.org/show_bug.cgi?id=246736
rdar://101325585

Reviewed by Antti Koivisto.

Calling scheduleFullStyleRebuild() is unnecessarily costly here. It is likely copy-paste from
methods that enter/exit fullscreen, which actually do need a rebuild because they need to
re-resolve style for all elements (un)matching :-webkit-full-screen-ancestor.

We can use PseudoClassChangeInvalidation which is more optimized for this purpose.

* Source/WebCore/dom/FullscreenManager.cpp:
(WebCore::FullscreenManager::setAnimatingFullscreen):
(WebCore::FullscreenManager::setFullscreenControlsHidden):
(WebCore::FullscreenManager::didExitFullscreen):
* Source/WebCore/dom/FullscreenManager.h:

Canonical link: https://commits.webkit.org/255748@main

Source/WebCore/dom/FullscreenManager.cpp

@@ -41,6 +41,7 @@
 #include "JSDOMPromiseDeferred.h"
 #include "Logging.h"
 #include "Page.h"
+#include "PseudoClassChangeInvalidation.h"
 #include "QualifiedName.h"
 #include "Settings.h"
 #include <wtf/LoggerHelper.h>
@@ -520,7 +521,7 @@ bool FullscreenManager::didExitFullscreen()
 
     m_fullscreenElement = nullptr;
     m_pendingFullscreenElement = nullptr;
-    scheduleFullStyleRebuild();
+    document().scheduleFullStyleRebuild();
 
     // When webkitCancelFullscreen is called, we call webkitExitFullscreen on the topDocument(). That
     // means that the events will be queued there. So if we have no events here, start the timer on
@@ -614,14 +615,13 @@ void FullscreenManager::setAnimatingFullscreen(bool flag)
 {
     if (m_isAnimatingFullscreen == flag)
         return;
-    m_isAnimatingFullscreen = flag;
 
     INFO_LOG(LOGIDENTIFIER, flag);
 
-    if (m_fullscreenElement && m_fullscreenElement->isDescendantOf(document())) {
-        m_fullscreenElement->invalidateStyleForSubtree();
-        scheduleFullStyleRebuild();
-    }
+    std::optional<Style::PseudoClassChangeInvalidation> styleInvalidation;
+    if (m_fullscreenElement)
+        emplace(styleInvalidation, *m_fullscreenElement, { { CSSSelector::PseudoClassAnimatingFullScreenTransition, flag } });
+    m_isAnimatingFullscreen = flag;
 }
 
 bool FullscreenManager::areFullscreenControlsHidden() const
@@ -636,12 +636,10 @@ void FullscreenManager::setFullscreenControlsHidden(bool flag)
 
     INFO_LOG(LOGIDENTIFIER, flag);
 
+    std::optional<Style::PseudoClassChangeInvalidation> styleInvalidation;
+    if (m_fullscreenElement)
+        emplace(styleInvalidation, *m_fullscreenElement, { { CSSSelector::PseudoClassFullScreenControlsHidden, flag } });
     m_areFullscreenControlsHidden = flag;
-
-    if (m_fullscreenElement && m_fullscreenElement->isDescendantOf(document())) {
-        m_fullscreenElement->invalidateStyleForSubtree();
-        scheduleFullStyleRebuild();
-    }
 }
 
 void FullscreenManager::clear()

Source/WebCore/dom/FullscreenManager.h

@@ -52,7 +52,6 @@ class FullscreenManager final : public CanMakeWeakPtr<FullscreenManager> {
     Frame* frame() const { return m_document.frame(); }
     Element* documentElement() const { return m_document.documentElement(); }
     Document::BackForwardCacheState backForwardCacheState() const { return m_document.backForwardCacheState(); }
-    void scheduleFullStyleRebuild() { m_document.scheduleFullStyleRebuild(); }
 
     // W3C Fullscreen API
     Element* fullscreenElement() const { return !m_fullscreenElementStack.isEmpty() ? m_fullscreenElementStack.last().get() : nullptr; }