Skip paint property update and visual rect update if no geometry change

third_party/WebKit/Source/core/layout/LayoutObject.cpp

Index: third_party/WebKit/Source/core/layout/LayoutObject.cpp
diff --git a/third_party/WebKit/Source/core/layout/LayoutObject.cpp b/third_party/WebKit/Source/core/layout/LayoutObject.cpp
index d62eab76425595a0e172f6c538666b4162abbc8c..4c651507e174243f7c4134bb8d15669691b94533 100644
--- a/third_party/WebKit/Source/core/layout/LayoutObject.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutObject.cpp
@@ -1629,6 +1629,7 @@ void LayoutObject::markAncestorsForOverflowRecalcIfNeeded() {
 void LayoutObject::setNeedsOverflowRecalcAfterStyleChange() {
   bool neededRecalc = needsOverflowRecalcAfterStyleChange();
   setSelfNeedsOverflowRecalcAfterStyleChange();
+  setNeedsPaintOffsetAndVisualRectUpdate();
   if (!neededRecalc)
     markAncestorsForOverflowRecalcIfNeeded();
 }
@@ -1728,11 +1729,21 @@ void LayoutObject::setStyle(PassRefPtr<ComputedStyle> style) {
   }
 
   if (diff.needsPaintInvalidationSubtree() ||
-      updatedDiff.needsPaintInvalidationSubtree())
+      updatedDiff.needsPaintInvalidationSubtree()) {
     setShouldDoFullPaintInvalidationIncludingNonCompositingDescendants();
-  else if (diff.needsPaintInvalidationObject() ||
-           updatedDiff.needsPaintInvalidationObject())
-    setShouldDoFullPaintInvalidation();
+  } else if (diff.needsPaintInvalidationObject() ||
+             updatedDiff.needsPaintInvalidationObject()) {
+    // TODO(wangxianzhu): For now LayoutSVGRoot::localVisualRect() depends on
+    // several styles. Refactor to avoid this special case.
+    if (isSVGRoot())
+      setShouldDoFullPaintInvalidation();
+    else
+      setShouldDoFullPaintInvalidationWithoutGeometryChange();
+  }
+
+  // Visibility affects visual rect.
+  if (oldStyle && oldStyle->visibility() != m_style->visibility())
+    setNeedsPaintOffsetAndVisualRectUpdate();
 
   // Text nodes share style with their parents but the paint properties don't
   // apply to them, hence the !isText() check.
@@ -3413,21 +3424,37 @@ inline void LayoutObject::markAncestorsForPaintInvalidation() {
       !parent
            ->shouldCheckForPaintInvalidationRegardlessOfPaintInvalidationState();
       parent = parent->paintInvalidationParent())
-    parent->m_bitfields.setChildShouldCheckForPaintInvalidation(true);
+    parent->m_bitfields.setMayNeedPaintInvalidation(true);
+}
+
+inline void LayoutObject::setNeedsPaintOffsetAndVisualRectUpdate() {
+  if (needsPaintOffsetAndVisualRectUpdate())
+    return;
+  m_bitfields.setNeedsPaintOffsetAndVisualRectUpdate(true);
+  for (LayoutObject* parent = paintInvalidationParent();
+       parent && !parent->needsPaintOffsetAndVisualRectUpdate();
+       parent = parent->paintInvalidationParent())
+    parent->m_bitfields.setNeedsPaintOffsetAndVisualRectUpdate(true);
 }
 
 void LayoutObject::setShouldInvalidateSelection() {
   if (!canUpdateSelectionOnRootLineBoxes())
     return;
   m_bitfields.setShouldInvalidateSelection(true);
-  markAncestorsForPaintInvalidation();
+  setMayNeedPaintInvalidation();
   frameView()->scheduleVisualUpdateForPaintInvalidationIfNeeded();
 }
 
 void LayoutObject::setShouldDoFullPaintInvalidation(
     PaintInvalidationReason reason) {
+  setNeedsPaintOffsetAndVisualRectUpdate();

[pdr., 2017/03/10 06:21:39]

Can this be called during paint invalidation? I think this might be what the
PropertyTreeBuilderContext DCHECKS are for (parentUpdated). If so, WDYT about
adding a DCHECK that needsPaintOffsetAndVisualRectUpdate is not set to true
during the prepaint walk?

[Xianzhu, 2017/03/10 17:43:05]

This can be called during paint invalidation (e.g. when we find paint offset
change in SPv2), but it should only change flags of objects that have not been
walked. The xxxUpdated flags can partly ensure the rule. We can add additional
flags in LayoutObject to enforce the rule. Will think more about this.

+  setShouldDoFullPaintInvalidationWithoutGeometryChange(reason);
+}
+
+void LayoutObject::setShouldDoFullPaintInvalidationWithoutGeometryChange(
+    PaintInvalidationReason reason) {
   // Only full invalidation reasons are allowed.
-  ASSERT(isFullPaintInvalidationReason(reason));
+  DCHECK(isFullPaintInvalidationReason(reason));
 
   bool isUpgradingDelayedFullToFull =
       m_bitfields.fullPaintInvalidationReason() ==
@@ -3448,6 +3475,11 @@ void LayoutObject::setShouldDoFullPaintInvalidation(
 }
 
 void LayoutObject::setMayNeedPaintInvalidation() {
+  setNeedsPaintOffsetAndVisualRectUpdate();
+  setMayNeedPaintInvalidationWithoutGeometryChange();
+}
+
+void LayoutObject::setMayNeedPaintInvalidationWithoutGeometryChange() {
   if (mayNeedPaintInvalidation())
     return;
   m_bitfields.setMayNeedPaintInvalidation(true);
@@ -3466,7 +3498,7 @@ void LayoutObject::setMayNeedPaintInvalidationAnimatedBackgroundImage() {
   if (mayNeedPaintInvalidationAnimatedBackgroundImage())
     return;
   m_bitfields.setMayNeedPaintInvalidationAnimatedBackgroundImage(true);
-  setMayNeedPaintInvalidation();
+  setMayNeedPaintInvalidationWithoutGeometryChange();
 }
 
 void LayoutObject::clearPaintInvalidationFlags() {
@@ -3477,10 +3509,10 @@ void LayoutObject::clearPaintInvalidationFlags() {
          paintInvalidationStateIsDirty());
 #endif
   clearShouldDoFullPaintInvalidation();
-  m_bitfields.setChildShouldCheckForPaintInvalidation(false);
   m_bitfields.setMayNeedPaintInvalidation(false);
   m_bitfields.setMayNeedPaintInvalidationSubtree(false);
   m_bitfields.setMayNeedPaintInvalidationAnimatedBackgroundImage(false);
+  m_bitfields.setNeedsPaintOffsetAndVisualRectUpdate(false);
   m_bitfields.setShouldInvalidateSelection(false);
   m_bitfields.setBackgroundChangedSinceLastPaintInvalidation(false);
 }