Enable subsequence caching for spv2

third_party/WebKit/Source/platform/graphics/paint/PaintChunk.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 PaintChunk_h
 #define PaintChunk_h
 
 #include "platform/geometry/FloatRect.h"
 #include "platform/graphics/paint/DisplayItem.h"
 #include "platform/graphics/paint/PaintChunkProperties.h"
 #include "wtf/Allocator.h"
 #include "wtf/Optional.h"
 #include <iosfwd>
 
 namespace blink {
 
 // A contiguous sequence of drawings with common paint properties.
 //
 // This is expected to be owned by the paint artifact which also owns the
 // related drawings.
 //
 // This is a Slimming Paint v2 class.
 struct PaintChunk {
     DISALLOW_NEW_EXCEPT_PLACEMENT_NEW();
     PaintChunk() : beginIndex(0), endIndex(0), knownToBeOpaque(false) { }
-    PaintChunk(unsigned begin, unsigned end, const DisplayItem::Id* chunkId, const PaintChunkProperties& props)
+    PaintChunk(size_t begin, size_t end, const DisplayItem::Id* chunkId, const PaintChunkProperties& props)
         : beginIndex(begin), endIndex(end), properties(props), knownToBeOpaque(false)
     {
         if (chunkId)
             id.emplace(*chunkId);
     }
 
-    unsigned size() const
+    size_t size() const
     {
         ASSERT(endIndex >= beginIndex);
         return endIndex - beginIndex;
     }
 
     // Check if a new PaintChunk (this) created in the latest paint matches an old
     // PaintChunk created in the previous paint.
     bool matches(const PaintChunk& old) const
     {
         // A PaintChunk without an id doesn't match any other PaintChunks.
         if (!id || !old.id)
             return false;
         if (*id != *old.id)
             return false;
 #if CHECK_DISPLAY_ITEM_CLIENT_ALIVENESS
         CHECK(id->client.isAlive());
 #endif
         // A chunk whose client is just created should not match any cached chunk,
         // even if it's id equals the old chunk's id (which may happen if this chunk's
         // client is just created at the same address of the old chunk's deleted client).
         return !id->client.isJustCreated();
     }
 
     // Index of the first drawing in this chunk.
-    unsigned beginIndex;
+    size_t beginIndex;
 
     // Index of the first drawing not in this chunk, so that there are
     // |endIndex - beginIndex| drawings in the chunk.
-    unsigned endIndex;
+    size_t endIndex;
 
     // Identifier of this chunk. If it has a value, it should be unique.
     // It's used to match a new chunk to a cached old chunk to track changes of chunk
     // contents, so the id should be stable across document cycles.
     // If the contents of the chunk can't be cached (e.g. it's created when PaintController
     // is skipping cache, normally because display items can't be uniquely identified),
     // id is nullopt so that the chunk won't match any other chunk.
     using Id = DisplayItem::Id;
     Optional<Id> id;
 
@@ skipping 22 matching lines @@
     return !(a == b);
 }
 
 // Redeclared here to avoid ODR issues.
 // See platform/testing/PaintPrinters.h.
 void PrintTo(const PaintChunk&, std::ostream*);
 
 } // namespace blink
 
 #endif // PaintChunk_h