Reduce memory usage in DelayedPersistentAllocation.

base/metrics/persistent_memory_allocator.h

Index: base/metrics/persistent_memory_allocator.h
diff --git a/base/metrics/persistent_memory_allocator.h b/base/metrics/persistent_memory_allocator.h
index 14f7a507a164bd23d4de06b7bb283e92817e2ae6..905d4ee1f2ef84c78e565ed4b04ced5d9269138b 100644
--- a/base/metrics/persistent_memory_allocator.h
+++ b/base/metrics/persistent_memory_allocator.h
@@ -850,8 +850,8 @@ class BASE_EXPORT DelayedPersistentAllocation {
   // The desired type and size of the allocated segment plus the offset
   // within it for the defined request.
   const uint32_t type_;
-  const size_t size_;
-  const size_t offset_;
+  const uint32_t size_;
+  const uint32_t offset_;
 
   // Flag indicating if allocation should be made iterable when done.
   const bool make_iterable_;