DisplayItemPropertyTreeBuilder: Support (2D) transform and scroll display items.

Source/platform/graphics/paint/DisplayItemPropertyTreeBuilder.cpp

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "platform/graphics/paint/DisplayItemPropertyTreeBuilder.h"
 
 #include "platform/graphics/paint/DisplayItem.h"
 #include "platform/graphics/paint/DisplayItemClipTree.h"
 #include "platform/graphics/paint/DisplayItemTransformTree.h"
+#include "platform/graphics/paint/ScrollDisplayItem.h"
 #include "platform/graphics/paint/Transform3DDisplayItem.h"
+#include "platform/graphics/paint/TransformDisplayItem.h"
 
 namespace blink {
 
 DisplayItemPropertyTreeBuilder::DisplayItemPropertyTreeBuilder()
     : m_transformTree(adoptPtr(new DisplayItemTransformTree))
     , m_clipTree(adoptPtr(new DisplayItemClipTree))
     , m_rangeBeginIndex(0)
     , m_currentIndex(0)
 {
     m_stateStack.append(BuilderState());
@@ skipping 51 matching lines @@
 static BeginDisplayItemClassification classifyBeginItem(const DisplayItem& beginDisplayItem)
 {
     ASSERT(beginDisplayItem.isBegin());
 
     BeginDisplayItemClassification result;
     DisplayItem::Type type = beginDisplayItem.type();
     if (DisplayItem::isTransform3DType(type)) {
         const auto& begin3D = static_cast<const BeginTransform3DDisplayItem&>(beginDisplayItem);
         result.matrix = begin3D.transform();
         result.transformKind = result.matrix.isIdentityOr2DTranslation() ? Only2DTranslation : RequiresTransformNode;
+    } else if (type == DisplayItem::BeginTransform) {
+        const auto& begin2D = static_cast<const BeginTransformDisplayItem&>(beginDisplayItem);
+        result.matrix = begin2D.transform();
+        result.transformKind = begin2D.transform().isIdentityOrTranslation() ? Only2DTranslation : RequiresTransformNode;
+    } else if (DisplayItem::isScrollType(type)) {
+        const auto& beginScroll = static_cast<const BeginScrollDisplayItem&>(beginDisplayItem);
+        const IntSize& offset = beginScroll.currentOffset();
+        result.matrix.translate(-offset.width(), -offset.height());
+        result.transformKind = Only2DTranslation;
     }
     return result;
 }
 
 } // namespace
 
 void DisplayItemPropertyTreeBuilder::processBeginItem(const DisplayItem& displayItem)
 {
     BeginDisplayItemClassification classification = classifyBeginItem(displayItem);
 
@@ skipping 62 matching lines @@
         rangeRecord.clipNodeIndex = current.clipNode;
         m_rangeRecords.append(rangeRecord);
     }
 
     // The current display item is a boundary.
     // The earliest the next range could begin is the next one.
     m_rangeBeginIndex = m_currentIndex + 1;
 }
 
 } // namespace blink