Move Partition Allocator into Chromium base.

base/sys_byteorder.h

Index: base/sys_byteorder.h
diff --git a/base/sys_byteorder.h b/base/sys_byteorder.h
index 8d9066c70228bfd7c36ec0cb3a2afe30dc006a2d..051f3e22c7cf696ba14d4b1a184b36fb20e681c3 100644
--- a/base/sys_byteorder.h
+++ b/base/sys_byteorder.h
@@ -46,6 +46,20 @@ inline uint64_t ByteSwap(uint64_t x) {
 #endif
 }
 
+inline uintptr_t ByteSwapUintPtrT(uintptr_t x) {
+#if defined(ARCH_CPU_64_BITS)
+  static_assert(sizeof(uint64_t) == sizeof(uintptr_t),
+                "uintptr_t not the same as uint64_t");
+  return ByteSwap(static_cast<uint64_t>(x));
+#elif defined(ARCH_CPU_32_BITS)
+  static_assert(sizeof(uint32_t) == sizeof(uintptr_t),
+                "uintptr_t not the same as uinti32_t");

[gab, 2016/12/09 21:01:56]

nit: typo s/uinti32_t/uint32_t/

+  return ByteSwap(static_cast<uint32_t>(x));
+#else
+#error architecture not supported
+#endif
+}
+
 // Converts the bytes in |x| from host order (endianness) to little endian, and
 // returns the result.
 inline uint16_t ByteSwapToLE16(uint16_t x) {