Peter Kasting

Avoid IWYU warnings on other namespaces for <algorithm>.

4

This is an extension of the logic already used for other STL headers.

### Description Windows allows the WS_HSCROLL and WS_VSCROLL styles (https://learn.microsoft.com/en-us/windows/win32/winmsg/window-styles) for scrollable windows. This would be useful for e.g. terminal emulators. I don't know how other platforms handle scrolling enough...

Fixes to allow building in -std=c++20 mode.

4

* Various kinds of math involving enums are deprecated, so replace with constexprs where necessary. * Types on both sides of "==" must match. Bug: chromium:1284275

[jumbo] Add begin()/end() to Slice.

2

This allows this type to meet the requirements of e.g. std::ranges::range, which is necessary for it to work with the std::span range constructor, or the "non-legacy" constructor for Chromium's base::span....

Win32 symbolizer does not call SymCleanup()

2

absl/debugging/symbolize_win32.inc implements the symbolizer code for win32. However, while it calls SymInitialize() to init the symbolizer, it never calls SymCleanup() to tear it down correctly. Per https://docs.microsoft.com/en-us/windows/win32/api/dbghelp/nf-dbghelp-symcleanup, "Failure to call...