[SPv2] Defer decision of raster invalidation after paint for changes z-index, transform, etc.

third_party/WebKit/Source/platform/graphics/paint/PaintChunker.h

 // 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.
 
 #ifndef PaintChunker_h
 #define PaintChunker_h
 
 #include "platform/PlatformExport.h"
 #include "platform/graphics/paint/DisplayItem.h"
 #include "platform/graphics/paint/PaintChunk.h"
@@ skipping 21 matching lines @@
 
     // Returns true if a new chunk is created.
     bool incrementDisplayItemIndex(const DisplayItem&);
     // Returns true if the last chunk is removed.
     bool decrementDisplayItemIndex();
 
     PaintChunk& paintChunkAt(size_t i) { return m_chunks[i]; }
     size_t lastChunkIndex() const { return m_chunks.isEmpty() ? kNotFound : m_chunks.size() - 1; }
     PaintChunk& lastChunk() { return m_chunks.last(); }
 
+    PaintChunk& findChunkByDisplayItemIndex(size_t index)
+    {
+        auto chunk = findChunkInVectorByDisplayItemIndex(m_chunks, index);
+        DCHECK(chunk != m_chunks.end());
+        return *chunk;
+    }
+
     void clear();
 
     // Releases the generated paint chunk list and resets the state of this
     // object.
     Vector<PaintChunk> releasePaintChunks();
 
 private:
     enum ItemBehavior {
         // Can be combined with adjacent items when building chunks.
         DefaultBehavior = 0,
 
         // Item requires its own paint chunk.
         RequiresSeparateChunk,
     };
 
     Vector<PaintChunk> m_chunks;
     Vector<ItemBehavior> m_chunkBehavior;
     Optional<PaintChunk::Id> m_currentChunkId;
     PaintChunkProperties m_currentProperties;
 };
 
 } // namespace blink
 
 #endif // PaintChunker_h