Changeset 257126 in webkit

Timestamp:

Feb 20, 2020 7:40:37 PM (4 years ago)

Author:

Alan Bujtas

Message:

[First paint] Let optional style recalcs go through while in visually-non-empty state.
​https://bugs.webkit.org/show_bug.cgi?id=208020
<rdar://problem/59636549>

Reviewed by Simon Fraser.

This is the final step to ensure we don't end up delaying the qualifiesAsVisuallyNonEmpty check when
the page happens to not trigger synchronous style recalcs.

Here is the optimized flow:
Optional style realc -> FrameView::styleAndRenderTreeDidChange -> qualifiesAsVisuallyNonEmpty -> Document::shouldScheduleLayout true.

This could be a slight regression in certain cases because now we let the optional style recalcs through and
only delay the redundant layouts (as opposed to delay both).

• dom/Document.cpp:

(WebCore::Document::scheduleStyleRecalc):
(WebCore::Document::shouldScheduleLayout):

Location:

trunk/Source/WebCore

Files:

• ChangeLog (modified) (1 diff)
• dom/Document.cpp (modified) (2 diffs)

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2020-02-20  Zalan Bujtas  <zalan@apple.com>
+
+        [First paint] Let optional style recalcs go through while in visually-non-empty state.
+        https://bugs.webkit.org/show_bug.cgi?id=208020
+        <rdar://problem/59636549>
+
+        Reviewed by Simon Fraser.
+
+        This is the final step to ensure we don't end up delaying the qualifiesAsVisuallyNonEmpty check when
+        the page happens to not trigger synchronous style recalcs.
+
+        Here is the optimized flow:
+        Optional style realc -> FrameView::styleAndRenderTreeDidChange -> qualifiesAsVisuallyNonEmpty -> Document::shouldScheduleLayout true.
+
+        This could be a slight regression in certain cases because now we let the optional style recalcs through and
+        only delay the redundant layouts (as opposed to delay both).
+
+        * dom/Document.cpp:
+        (WebCore::Document::scheduleStyleRecalc):
+        (WebCore::Document::shouldScheduleLayout):
+
 2020-02-20  Eric Carlson  <eric.carlson@apple.com>
 

trunk/Source/WebCore/dom/Document.cpp

@@ -1873 +1873 @@
 
     ASSERT(childNeedsStyleRecalc() || m_needsFullStyleRebuild);
-    auto shouldThrottleStyleRecalc = [&] {
-        if (!view() || !view()->isVisuallyNonEmpty())
-            return false;
-        if (!page() || !page()->chrome().client().renderingUpdateThrottlingIsActive())
-            return false;
-        return true;
-    };
-
-    if (shouldThrottleStyleRecalc())
-        return;
+    if (page() && page()->chrome().client().renderingUpdateThrottlingIsActive()) {
+        // Do not run optional style recalcs while we throttle painting.
+        return;
+    }
 
     m_styleRecalcTimer.startOneShot(0_s);
@@ -3136 +3130 @@
     if (styleScope().hasPendingSheetsBeforeBody())
         return false;
-    if (page() && page()->chrome().client().renderingUpdateThrottlingIsActive() && view() && view()->isVisuallyNonEmpty())
+    if (page() && page()->chrome().client().renderingUpdateThrottlingIsActive())
         return false;
-
+    if (view() && !view()->isVisuallyNonEmpty())
+        return false;
     return true;
 }