SnapManager implementation using V8 Extras - {WIP}

third_party/WebKit/Source/core/page/scrolling/SnapCoordinator.cpp

Index: third_party/WebKit/Source/core/page/scrolling/SnapCoordinator.cpp
diff --git a/third_party/WebKit/Source/core/page/scrolling/SnapCoordinator.cpp b/third_party/WebKit/Source/core/page/scrolling/SnapCoordinator.cpp
index 022f7a2a272cf758ab4af7fe93731a8109ff8664..9b5bc15b998e25fa96dd9a345b176447db31afa6 100644
--- a/third_party/WebKit/Source/core/page/scrolling/SnapCoordinator.cpp
+++ b/third_party/WebKit/Source/core/page/scrolling/SnapCoordinator.cpp
@@ -15,18 +15,18 @@
 
 namespace blink {
 
-SnapCoordinator::SnapCoordinator()
-    : m_snapContainers()
+SnapCoordinator* SnapCoordinator::create(Client* client)
 {
+    return new SnapCoordinator(client);
 }
 
-SnapCoordinator::~SnapCoordinator() { }
-
-SnapCoordinator* SnapCoordinator::create()
+SnapCoordinator::SnapCoordinator(Client* client)
+    : m_client(client)
 {
-    return new SnapCoordinator();
 }
 
+SnapCoordinator::~SnapCoordinator() { }
+
 // Returns the scroll container that can be affected by this snap area.
 static LayoutBox* findSnapContainer(const LayoutBox& snapArea)
 {
@@ -147,6 +147,27 @@ Vector<double> SnapCoordinator::snapOffsets(const ContainerNode& element, Scroll
     return result;
 }
 
+
+
+void SnapCoordinator::notifyLayoutUpdated()
+{
+    // TODO(majidvp): This should be replaced with compositor worker precommit
+    for (const LayoutBox* container : m_snapContainers) {
+        ContainerNode& containerNode =  toContainerNode(*container->node());
+        SnapOffsets newOffsets;
+        newOffsets.horizontal = snapOffsets(containerNode, HorizontalScrollbar);
+        newOffsets.vertical = snapOffsets(containerNode, VerticalScrollbar);
+
+        // report only if it is different from the cached value
+        if (m_offsetMap.contains(container) && m_offsetMap.get(container) == newOffsets)
+            continue;
+        m_offsetMap.set(container, newOffsets);
+        if (m_client)
+            m_client->didUpdateSnapOffsets(*container, newOffsets);
+    }
+}
+
+
 #ifndef NDEBUG
 
 void SnapCoordinator::showSnapAreaMap()
@@ -168,4 +189,9 @@ void SnapCoordinator::showSnapAreasFor(const LayoutBox* container)
 
 #endif
 
+bool operator==(const SnapOffsets& a, const SnapOffsets& b)
+{
+    return a.horizontal == b.horizontal && a.vertical == b.vertical;
+}
+
 } // namespace blink