Abseil LTS 20250107.rc1

What's New

absl::StringResizeAndOverwrite(): A new function in absl/strings/resize_and_overwrite.h that acts as a polyfill for C++23's std::basic_string::resize_and_overwrite. This allows for efficient resizing and in-place initialization of strings, avoiding the overhead of default initialization, which is particularly useful when working with C-style APIs that write directly to a buffer. See #1136 (comment) for performance notes.
absl::chunked_queue: A new container in absl/container/chunked_queue.h optimized for use as a FIFO (First-In, First-Out) queue.
absl::linked_hash_map and absl::linked_hash_set: New hash containers that maintain iteration order matching the insertion order. These are available in absl/container/linked_hash_map.h and absl/container/linked_hash_set.h.
absl::down_cast: Added to absl/base/casts.h. This function provides a safer way to perform downcasts in a polymorphic type hierarchy. In debug builds (or when hardened asserts are enabled), it uses dynamic_cast to verify the validity of the cast and terminates the program if the cast is invalid. In optimized builds, it uses static_cast for performance.

Mutex Deprecations: Legacy Mutex methods and MutexLock pointer constructors have been marked as deprecated. Users should migrate to the recommended APIs.
The polyfill type absl::string_view is now an alias for std::string_view in all builds. (9ebd93a)

Baseline: 1e566d9