Ensure filter and reflection outsets are applied on paint invalidation rect

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

Index: third_party/WebKit/Source/core/layout/LayoutBox.cpp
diff --git a/third_party/WebKit/Source/core/layout/LayoutBox.cpp b/third_party/WebKit/Source/core/layout/LayoutBox.cpp
index 70e2509cb39ec661154035ac38b7e44ec691b6e9..361f67c6e53caf5e67078e3b0d0dd9d89fe03ea8 100644
--- a/third_party/WebKit/Source/core/layout/LayoutBox.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutBox.cpp
@@ -1971,10 +1971,7 @@ LayoutRect LayoutBox::localOverflowRectForPaintInvalidation() const
 
 bool LayoutBox::mapToVisualRectInAncestorSpace(const LayoutBoxModelObject* ancestor, LayoutRect& rect, VisualRectFlags visualRectFlags) const
 {
-    // We need to inflate the paint invalidation rect before we use paintInvalidationState,
-    // else we would forget to inflate it for the current layoutObject. FIXME: If these were
-    // included into the visual overflow for paint invalidation, we wouldn't have this issue.
-    inflatePaintInvalidationRectForReflectionAndFilter(rect);
+    inflateVisualRectForReflectionAndFilter(rect);
 
     if (ancestor == this) {
         // The final rect returned is always in the physical coordinate space of the ancestor.
@@ -1983,10 +1980,24 @@ bool LayoutBox::mapToVisualRectInAncestorSpace(const LayoutBoxModelObject* ances
     }
 
     bool ancestorSkipped;
-    LayoutObject* container = this->container(ancestor, &ancestorSkipped);
+    bool filterOrReflectionSkipped;
+    LayoutObject* container = this->container(ancestor, &ancestorSkipped, &filterOrReflectionSkipped);
     if (!container)
         return true;
 
+    if (filterOrReflectionSkipped) {
+        // Apply filter and reflection outsets between this object and container or ancestor.
+        for (LayoutObject* parent = this->parent(); parent && parent != container; parent = parent->parent()) {
+            if (parent->isBox())
+                toLayoutBox(parent)->inflateVisualRectForReflectionAndFilter(rect);

[chrishtr, 2016/05/02 22:16:30]

Doesn't |rect| need to be in the space of parent| for this to be valid?

[Xianzhu, 2016/05/02 22:21:48]

Not necessary. The function just inflate the rect by maximum outsets of the
filter effect. The result rect covers all the affected area of this object with
the ancestor filter applied.

[chrishtr, 2016/05/02 22:51:50]

But if the rect is not originally in the space of the box, how can these outsets
possibly be applied correctly?

+            if (parent == ancestor) {
+                // We meet ancestor before container.
+                ASSERT(ancestorSkipped);
+                break;
+            }
+        }
+    }
+
     // The rect we compute at each step is shifted by our x/y offset in the parent container's coordinate space.
     // Only when we cross a writing mode boundary will we have to possibly flipForWritingMode (to convert into a more
     // appropriate offset corner for the enclosing container).
@@ -2043,7 +2054,7 @@ bool LayoutBox::mapToVisualRectInAncestorSpace(const LayoutBoxModelObject* ances
         return container->mapToVisualRectInAncestorSpace(ancestor, rect, visualRectFlags);
 }
 
-void LayoutBox::inflatePaintInvalidationRectForReflectionAndFilter(LayoutRect& paintInvalidationRect) const
+void LayoutBox::inflateVisualRectForReflectionAndFilter(LayoutRect& paintInvalidationRect) const
 {
     if (!RuntimeEnabledFeatures::cssBoxReflectFilterEnabled() && hasReflection())
         paintInvalidationRect.unite(reflectedRect(paintInvalidationRect));