Implement CSS: scroll-boundary-behavior

third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp

Index: third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp
diff --git a/third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp b/third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp
index 2a04d2e00db8e4dc9668733af5e47cc4cdb1961e..58127b8afcda7e7d850a9d60bd94a3b80f41e9a4 100644
--- a/third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp
+++ b/third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp
@@ -81,6 +81,7 @@
 #include "platform/wtf/CurrentTime.h"
 #include "platform/wtf/text/StringBuilder.h"
 #include "public/platform/WebLayerStickyPositionConstraint.h"
+#include "public/platform/WebScrollBoundaryBehavior.h"
 
 namespace blink {
 
@@ -1138,11 +1139,27 @@ void CompositedLayerMapping::UpdateGraphicsLayerGeometry(
   UpdateShouldFlattenTransform();
   UpdateChildrenTransform();
   UpdateScrollParent(ScrollParent());
+  UpdateScrollBoundaryBehavior();
   RegisterScrollingLayers();
 
   UpdateCompositingReasons();
 }
 
+void CompositedLayerMapping::UpdateScrollBoundaryBehavior() {
+  EScrollBoundaryBehavior behavior_x =
+      GetLayoutObject().StyleRef().ScrollBoundaryBehaviorX();
+  EScrollBoundaryBehavior behavior_y =
+      GetLayoutObject().StyleRef().ScrollBoundaryBehaviorY();
+  if (scrolling_contents_layer_) {
+    scrolling_contents_layer_->SetScrollBoundaryBehavior(
+        WebScrollBoundaryBehavior(
+            static_cast<WebScrollBoundaryBehavior::ScrollBoundaryBehaviorType>(
+                behavior_x),
+            static_cast<WebScrollBoundaryBehavior::ScrollBoundaryBehaviorType>(
+                behavior_y)));
+  }
+}
+
 void CompositedLayerMapping::UpdateMainGraphicsLayerGeometry(
     const IntRect& relative_compositing_bounds,
     const IntRect& local_compositing_bounds,