Handle resize in PaintPropertyTreeBuilder::updateForObjectSizeAndLocation()

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

Index: third_party/WebKit/Source/core/paint/PaintPropertyTreeBuilder.cpp
diff --git a/third_party/WebKit/Source/core/paint/PaintPropertyTreeBuilder.cpp b/third_party/WebKit/Source/core/paint/PaintPropertyTreeBuilder.cpp
index 79b3fab9b93dc65391d72c4414519e730052fe7c..a67e8e5d94f95ebe08e0e8f56cf528dd8ea7529a 100644
--- a/third_party/WebKit/Source/core/paint/PaintPropertyTreeBuilder.cpp
+++ b/third_party/WebKit/Source/core/paint/PaintPropertyTreeBuilder.cpp
@@ -1043,7 +1043,7 @@ void PaintPropertyTreeBuilder::updatePaintOffset(
   }
 }
 
-void PaintPropertyTreeBuilder::updateForObjectLocation(
+void PaintPropertyTreeBuilder::updateForObjectSizeAndLocation(
     const LayoutObject& object,
     PaintPropertyTreeBuilderContext& context) {
   if (object.isBoxModelObject()) {
@@ -1051,18 +1051,37 @@ void PaintPropertyTreeBuilder::updateForObjectLocation(
     updatePaintOffsetTranslation(toLayoutBoxModelObject(object), context);
   }
 
-  if (object.paintOffset() == context.current.paintOffset)
-    return;
+  if (object.isBox()) {
+    const LayoutBox& box = toLayoutBox(object);
+    if (box.size() != box.previousSize() &&
+        // The overflow clip paint property depends on the border box rect
+        // through overflowClipRect(). The border box rect's size equals the
+        // frame rect's size so we trigger a paint property update when the
+        // frame rect changes.
+        (box.shouldClipOverflow() ||
+         // The used value of CSS clip may depend on size of the box, e.g.
+         // for clip: rect(auto auto auto -5px).
+         box.hasClip() ||
+         // Relative lengths (e.g., percentage values) in transform,
+         // perspective, transform-origin, and perspective-origin can depend on
+         // the size of the frame rect, so force a property update if it
+         // changes. TODO(pdr): We only need to update properties if there are
+         // relative lengths.
+         box.styleRef().hasTransform() || box.styleRef().hasPerspective()))
+      box.getMutableForPainting().setNeedsPaintPropertyUpdate();
+  }
 
-  // Many paint properties depend on paint offset so we force an update of
-  // the entire subtree on paint offset changes.
-  context.forceSubtreeUpdate = true;
+  if (object.paintOffset() != context.current.paintOffset) {
+    // Many paint properties depend on paint offset so we force an update of
+    // the entire subtree on paint offset changes.
+    context.forceSubtreeUpdate = true;
 
-  if (RuntimeEnabledFeatures::slimmingPaintV2Enabled()) {
-    object.getMutableForPainting().setShouldDoFullPaintInvalidation(
-        PaintInvalidationLocationChange);
+    if (RuntimeEnabledFeatures::slimmingPaintV2Enabled()) {
+      object.getMutableForPainting().setShouldDoFullPaintInvalidation(
+          PaintInvalidationLocationChange);
+    }
+    object.getMutableForPainting().setPaintOffset(context.current.paintOffset);
   }
-  object.getMutableForPainting().setPaintOffset(context.current.paintOffset);
 }
 
 void PaintPropertyTreeBuilder::updatePropertiesForSelf(
@@ -1070,7 +1089,7 @@ void PaintPropertyTreeBuilder::updatePropertiesForSelf(
     PaintPropertyTreeBuilderContext& context) {
   // This is not in FindObjectPropertiesNeedingUpdateScope because paint offset
   // can change without needsPaintPropertyUpdate.

[pdr., 2017/03/01 23:38:38]

Nit: can you mention size changing in this comment?

-  updateForObjectLocation(object, context);
+  updateForObjectSizeAndLocation(object, context);
 
 #if DCHECK_IS_ON()
   FindObjectPropertiesNeedingUpdateScope checkNeedsUpdateScope(object, context);