Implement Internals::mainThreadScrollingReasons for SPV2

third_party/WebKit/Source/core/frame/FrameView.cpp

 /*
  * Copyright (C) 1998, 1999 Torben Weis <weis@kde.org>
  *                     1999 Lars Knoll <knoll@kde.org>
  *                     1999 Antti Koivisto <koivisto@kde.org>
  *                     2000 Dirk Mueller <mueller@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
  *           (C) 2006 Graham Dennis (graham.dennis@gmail.com)
  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
@@ skipping 4878 matching lines @@
     if (!frame->isLocalFrame())
       continue;
     reasons |=
         toLocalFrame(frame)->view()->mainThreadScrollingReasonsPerFrame();
   }
 
   return reasons;
 }
 
 String FrameView::mainThreadScrollingReasonsAsText() const {
+  if (RuntimeEnabledFeatures::slimmingPaintV2Enabled()) {
+    DCHECK(lifecycle().state() >= DocumentLifecycle::PrePaintClean);
+
+    // Slimming paint v2 stores main thread scrolling reasons on property
+    // trees instead of in |m_mainThreadScrollingReasons|.
+    MainThreadScrollingReasons reasons = 0;
+    if (const auto* scrollNode = scroll())
+      reasons |= scrollNode->mainThreadScrollingReasons();
+    return String(
+        MainThreadScrollingReason::mainThreadScrollingReasonsAsText(reasons)
+            .c_str());
+  }
+
   DCHECK(lifecycle().state() >= DocumentLifecycle::CompositingClean);
   if (layerForScrolling() && layerForScrolling()->platformLayer()) {
     String result(
         MainThreadScrollingReason::mainThreadScrollingReasonsAsText(
             layerForScrolling()->platformLayer()->mainThreadScrollingReasons())
             .c_str());
     return result;
   }
 
   String result(MainThreadScrollingReason::mainThreadScrollingReasonsAsText(
@@ skipping 77 matching lines @@
   // This is the top-level frame, so no mapping necessary.
   if (m_frame->isMainFrame())
     return;
 
   LayoutRect viewportIntersectionRect(remoteViewportIntersection());
   transformState.move(
       LayoutSize(-viewportIntersectionRect.x(), -viewportIntersectionRect.y()));
 }
 
 }  // namespace blink