Add main thread scrolling reasons to GraphicsLayer::layerTreeAsJSON.

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

 /*
  * Copyright (C) 2014 Google Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  */
 
 #include "platform/graphics/GraphicsLayerDebugInfo.h"
 
 #include "base/trace_event/trace_event_argument.h"
+#include "platform/scroll/MainThreadScrollingReason.h"
+
+#include <vector>
 
 namespace blink {
 
 GraphicsLayerDebugInfo::GraphicsLayerDebugInfo()
     : m_compositingReasons(CompositingReasonNone)
     , m_squashingDisallowedReasons(SquashingDisallowedReasonsNone)
     , m_ownerNodeId(0)
+    , m_mainThreadScrollingReasons(0)
 {
 }
 
 GraphicsLayerDebugInfo::~GraphicsLayerDebugInfo() { }
 
 std::unique_ptr<base::trace_event::TracedValue> GraphicsLayerDebugInfo::asTracedValue() const
 {
     std::unique_ptr<base::trace_event::TracedValue> tracedValue(
         new base::trace_event::TracedValue());
     appendAnnotatedInvalidateRects(tracedValue.get());
     appendCompositingReasons(tracedValue.get());
     appendSquashingDisallowedReasons(tracedValue.get());
     appendOwnerNodeId(tracedValue.get());
+    appendMainThreadScrollingReasons(tracedValue.get());
     return tracedValue;
 }
 
 void GraphicsLayerDebugInfo::appendAnnotatedInvalidateRects(base::trace_event::TracedValue* tracedValue) const
 {
     tracedValue->BeginArray("annotated_invalidation_rects");
     for (const auto& annotatedRect : m_previousInvalidations) {
         const FloatRect& rect = annotatedRect.rect;
         tracedValue->BeginDictionary();
         tracedValue->BeginArray("geometry_rect");
@@ skipping 46 matching lines @@
     };
     m_invalidations.append(annotatedRect);
 }
 
 void GraphicsLayerDebugInfo::clearAnnotatedInvalidateRects()
 {
     m_previousInvalidations.clear();
     m_previousInvalidations.swap(m_invalidations);
 }
 
+void GraphicsLayerDebugInfo::appendMainThreadScrollingReasons(base::trace_event::TracedValue* tracedValue) const
+{
+    std::vector<std::string> reasons = MainThreadScrollingReason::mainThreadScrollingReasonsAsStringArray(m_mainThreadScrollingReasons);
+    size_t arraySize = reasons.size();
+    tracedValue->BeginArray("main_thread_scrolling_reasons");
+    for (size_t i = 0; i < arraySize; ++i) {
+        tracedValue->AppendString(reasons[i]);
+    }
+    tracedValue->EndArray();
+}
+
 } // namespace blink