Tweak priorities of paint invalidation reasons

third_party/WebKit/Source/core/paint/BoxPaintInvalidator.cpp

Index: third_party/WebKit/Source/core/paint/BoxPaintInvalidator.cpp
diff --git a/third_party/WebKit/Source/core/paint/BoxPaintInvalidator.cpp b/third_party/WebKit/Source/core/paint/BoxPaintInvalidator.cpp
index a1625c3af3e9e00c5a9f149d6868482d0e95d497..04b3f8d23f47280a96b2335b2a011b749bfccc8f 100644
--- a/third_party/WebKit/Source/core/paint/BoxPaintInvalidator.cpp
+++ b/third_party/WebKit/Source/core/paint/BoxPaintInvalidator.cpp
@@ -105,7 +105,7 @@ PaintInvalidationReason BoxPaintInvalidator::computePaintInvalidationReason()
 {
     PaintInvalidationReason reason = ObjectPaintInvalidator(m_box, m_context).computePaintInvalidationReason();
 
-    if (reason != PaintInvalidationDelayedFull && isFullPaintInvalidationReason(reason))
+    if (isImmediateFullPaintInvalidationReason(reason) || reason == PaintInvalidationNone)
         return reason;
 
     if (m_box.mayNeedPaintInvalidationAnimatedBackgroundImage() && !m_box.backgroundIsKnownToBeObscured())
@@ -164,11 +164,6 @@ PaintInvalidationReason BoxPaintInvalidator::computePaintInvalidationReason()
     if (oldBorderBoxSize == newBorderBoxSize)
         return reason;
 
-    // LayoutBox::incrementallyInvalidatePaint() depends on positionFromPaintInvalidationBacking
-    // which is not available when slimmingPaintOffsetCachingEnabled.
-    if (RuntimeEnabledFeatures::slimmingPaintInvalidationEnabled() && (style.hasBoxDecorations() || style.hasBackground()))
-        return PaintInvalidationBorderBoxChange;
-
     // See another hasNonCompositedScrollbars() callsite above.
     if (m_box.hasNonCompositedScrollbars())
         return PaintInvalidationBorderBoxChange;
@@ -190,7 +185,7 @@ PaintInvalidationReason BoxPaintInvalidator::computePaintInvalidationReason()
     if (oldBorderBoxSize.height() != newBorderBoxSize.height() && m_box.mustInvalidateBackgroundOrBorderPaintOnHeightChange())
         return PaintInvalidationBorderBoxChange;
 
-    if (reason == PaintInvalidationNone && (style.hasBackground() || style.hasBoxDecorations()))
+    if (reason == PaintInvalidationProbablyNone && (style.hasBackground() || style.hasBoxDecorations()))
         reason = PaintInvalidationIncremental;
 
     return reason;