Add main thread scrolling reasons to GraphicsLayer::layerTreeAsJSON.

third_party/WebKit/Source/platform/graphics/GraphicsLayer.cpp

 /*
  * Copyright (C) 2009 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 1238 matching lines @@
     }
 }
 
 std::unique_ptr<base::trace_event::ConvertableToTraceFormat> GraphicsLayer::TakeDebugInfo(cc::Layer* layer)
 {
     std::unique_ptr<base::trace_event::TracedValue> tracedValue(m_debugInfo.asTracedValue());
     tracedValue->SetString("layer_name", WTF::StringUTF8Adaptor(debugName(layer)).asStringPiece());
     return std::move(tracedValue);
 }
 
+void GraphicsLayer::didUpdateMainThreadScrollingReasons()
+{
+    m_debugInfo.setMainThreadScrollingReasons(platformLayer()->mainThreadScrollingReasons());
+}
+
 PaintController& GraphicsLayer::getPaintController()
 {
     RELEASE_ASSERT(drawsContent());
     if (!m_paintController)
         m_paintController = PaintController::create();
     return *m_paintController;
 }
 
 void GraphicsLayer::setElementId(const CompositorElementId& id)
 {
@@ skipping 105 matching lines @@
 {
     if (!layer) {
         fprintf(stderr, "Cannot showGraphicsLayerTree for (nil).\n");
         return;
     }
 
     String output = layer->layerTreeAsText(blink::LayerTreeIncludesDebugInfo);
     fprintf(stderr, "%s\n", output.utf8().data());
 }
 #endif