From ee6e6d3e45af1f7210e144a17f14fb21a7e86588 Mon Sep 17 00:00:00 2001
From: mikt <mikt@google.com>
Date: Tue, 30 Jan 2024 03:09:24 +0000
Subject: [PATCH] [PA] Fix InternalAllocator for GCC builds

Internal Allocator has a few missing member functions, that are required
as a part of named requirement Allocator.
https://en.cppreference.com/w/cpp/named_req/Allocator

It broke builds on GCC, so adding these to fix.
https://crrev.com/c/5196856/comments/0c4bbfd9_6433016b

Change-Id: Ifce5f3e47c94c7bb1e298ac4cd7d0d1e4c6de59c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5231905
Commit-Queue: Mikihito Matsuura <mikt@google.com>
Reviewed-by: Kalvin Lee <kdlee@chromium.org>
Reviewed-by: Takashi Sakamoto <tasak@google.com>
Cr-Commit-Position: refs/heads/main@{#1253709}
---
 .../internal_allocator_forward.h              | 21 +++++++++++++++----
 1 file changed, 17 insertions(+), 4 deletions(-)

diff --git a/base/allocator/partition_allocator/src/partition_alloc/internal_allocator_forward.h b/base/allocator/partition_allocator/src/partition_alloc/internal_allocator_forward.h
index 45fec29f8cc93..b31a145ff6e99 100644
--- a/base/allocator/partition_allocator/src/partition_alloc/internal_allocator_forward.h
+++ b/base/allocator/partition_allocator/src/partition_alloc/internal_allocator_forward.h
@@ -27,11 +27,24 @@ PartitionRoot& InternalAllocatorRoot();
 template <typename T>
 class InternalAllocator {
  public:
-  // Member types required by allocator completeness requirements.
   using value_type = T;
-  using size_type = std::size_t;
-  using difference_type = std::ptrdiff_t;
-  using propagate_on_container_move_assignment = std::true_type;
+  using is_always_equal = std::true_type;
+
+  InternalAllocator() = default;
+
+  template <typename U>
+  InternalAllocator(const InternalAllocator<U>&) {}  // NOLINT
+
+  template <typename U>
+  InternalAllocator& operator=(const InternalAllocator<U>&) {
+    return *this;
+  }
+
+  template <typename U>
+  bool operator==(const InternalAllocator<U>&) {
+    // InternalAllocator<T> can free allocations made by InternalAllocator<U>.
+    return true;
+  }
 
   value_type* allocate(std::size_t count);