Reuse cc::PictureLayers when possible for SPv2.

third_party/WebKit/Source/platform/graphics/paint/PaintArtifact.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 "platform/graphics/paint/PaintArtifact.h"
 
 #include "platform/TraceEvent.h"
 #include "platform/geometry/IntRect.h"
 #include "platform/graphics/GraphicsLayer.h"
 #include "platform/graphics/paint/DrawingDisplayItem.h"
 #include "public/platform/WebDisplayItemList.h"
 #include "third_party/skia/include/core/SkRegion.h"
 
 namespace blink {
 
 namespace {
 
 void computeChunkBoundsAndOpaqueness(const DisplayItemList& displayItems, Vector<PaintChunk>& paintChunks)
 {
     for (PaintChunk& chunk : paintChunks) {
         FloatRect bounds;
         SkRegion knownToBeOpaqueRegion;
         for (const DisplayItem& item : displayItems.itemsInPaintChunk(chunk)) {
+            bounds.unite(FloatRect(item.client().visualRect()));
             if (!item.isDrawing())
                 continue;
             const auto& drawing = static_cast<const DrawingDisplayItem&>(item);
             if (const SkPicture* picture = drawing.picture()) {
-                const SkRect& pictureRect = picture->cullRect();
-                bounds.unite(pictureRect);
                 if (drawing.knownToBeOpaque()) {
-                    // TODO(pdr): This may be too conservative and fail due to
-                    // floating point precision issues.
+                    // TODO(pdr): It may be too conservative to round in to the enclosedIntRect.
                     SkIRect conservativelyRoundedPictureRect;
+                    const SkRect& pictureRect = picture->cullRect();
                     pictureRect.roundIn(&conservativelyRoundedPictureRect);
                     knownToBeOpaqueRegion.op(conservativelyRoundedPictureRect, SkRegion::kUnion_Op);
                 }
             }
         }
         chunk.bounds = bounds;
         if (knownToBeOpaqueRegion.contains(enclosingIntRect(bounds)))
             chunk.knownToBeOpaque = true;
     }
 }
@@ skipping 57 matching lines @@
     TRACE_EVENT0("blink,benchmark", "PaintArtifact::appendToWebDisplayItemList");
     size_t visualRectIndex = 0;
     for (const DisplayItem& displayItem : m_displayItemList) {
         displayItem.appendToWebDisplayItemList(m_displayItemList.visualRect(visualRectIndex), list);
         visualRectIndex++;
     }
     list->setIsSuitableForGpuRasterization(isSuitableForGpuRasterization());
 }
 
 } // namespace blink