Simplify DefaultAllocator::Quantizer using partitionAllocActualSize()

Source/wtf/QuantizedAllocation.h

-/*
- * Copyright (C) 2013 Google Inc. All rights reserved.
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- * modification, are permitted provided that the following conditions are
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-
-#ifndef WTF_QuantizedAllocation_h
-#define WTF_QuantizedAllocation_h
-
-// DESCRIPTION
-// QuantizedAllocation::quantizedSize() rounds up the specific size such that:
-// 1) Granularity of allocation sizes is >1, and grows as a fraction of the
-// allocation size. This property can be used to limit bucket fragmentation
-// when sitting on top of a high-granularity allocator such as PartitionAlloc.
-// 2) The sizes are likely (but not guaranteed) to correspond to exact "bucket
-// sizes" of any underlying allocator that implements standard bucketing.
-// This currently includes tcmalloc, Windows LFH and PartitionAlloc.
-
-#include "wtf/Assertions.h"
-#include "wtf/WTFExport.h"
-#include <limits.h>
-
-namespace WTF {
-
-class WTF_EXPORT QuantizedAllocation {
-public:
-    // Allocations above 32k are rounded to 4k (which is typically the system
-    // page size).
-    static const size_t kMaxAllocation = 32768;
-    static const size_t kMaxRounding = 4096;
-
-    // This is the minimum granularity of allocation, currently 8 bytes.
-    static const size_t kMinRounding = 8;
-
-    // After 128 bytes, the granularity doubles, and proceeds to double again
-    // as the allocation size further doubles.
-    static const size_t kMinRoundingLimit = 128;
-    static const size_t kTableSize = kMaxAllocation / kMinRoundingLimit;
-
-    // Using "unsigned" is not a limitation because Chromium's max malloc() is
-    // 2GB even on 64-bit.
-    static const size_t kMaxUnquantizedAllocation = INT_MAX - kMaxRounding;
-
-    static void init();
-
-    template<typename T>
-    static size_t quantizedSize(size_t count)
-    {
-        RELEASE_ASSERT(count <= kMaxUnquantizedAllocation / sizeof(T));
-        size_t size = count * sizeof(T);
-        size_t roundToLessOne;
-        if (UNLIKELY(size >= kMaxAllocation))
-            roundToLessOne = kMaxRounding - 1;
-        else
-            roundToLessOne = table[size / kMinRoundingLimit];
-        return (size + roundToLessOne) & ~roundToLessOne;
-    }
-
-private:
-    static unsigned short table[kTableSize];
-};
-
-} // namespace WTF
-
-#endif // WTF_QuantizedAllocation_h