.gclient

solutions = [
  { "name"        : 'src',
    "url"         : 'https://github.com/Wowfunhappy/chromium-legacy.git',
    "deps_file"   : 'DEPS',
    "managed"     : False,
    "custom_deps" : {
    },
    "custom_vars": {
      "checkout_pgo_profiles": True,
    },
  },
]

args.gn

clang_use_chrome_plugins=false
treat_warnings_as_errors=false
use_custom_libcxx = false

is_debug = false
is_component_build = false
is_official_build = true
symbol_level = 0
enable_dsyms = false
enable_stripping = false

mac_deployment_target = "10.7"
mac_min_system_version = "10.7"

enable_nacl = false
media_use_ffmpeg = true
media_use_libvpx = true
proprietary_codecs = true
ffmpeg_branding = "Chrome"

build.sh

#!/bin/bash
mkdir -pv chromium-project && cd chromium-project
mkdir -pv clang-master && pushd clang-master && curl -LOJ https://github.com/blueboxd/llvm-project/releases/download/main/main.tar.xz && tar xvf main.tar.xz
popd
git clone https://chromium.googlesource.com/chromium/tools/depot_tools.git && export PATH=`pwd`/depot_tools:"$PATH"
mkdir -pv chromium-legacy && cd chromium-legacy
curl -OJ https://gist.githubusercontent.com/Wowfunhappy/0fcc5f6aab77794e9decbd8e7f4d4469/raw/dea92eae9afd416c74efccd94ee3688b1a8de76a/.gclient
gclient sync -v --no-history
pushd src/third_party/skia
git remote add for-lion https://github.com/Wowfunhappy/skia.git
git fetch for-lion && git checkout for-lion && git checkout for-lion -- .
popd
pushd src/v8/src
curl -OJ https://gist.githubusercontent.com/blueboxd/c1f355fb6fe829e98ff5453880683993/raw/97a23ba80d28005f6072053920d979be87213193/sp_mut.cc
cd ../
cat BUILD.gn | sed -e 's#"src/wasm/wasm-code-manager.h",#"src/wasm/wasm-code-manager.h",\'$'\n    "src/sp_mut.cc",#g' > BUILD.gn.tmp && mv -fv BUILD.gn.tmp BUILD.gn
popd
pushd src/third_party/angle/src/libANGLE/renderer/
curl -OJ https://gist.githubusercontent.com/blueboxd/c1f355fb6fe829e98ff5453880683993/raw/65ba4558a17eb47feb38729a87b8d8976d5bb8ad/driver_utils_mac.mm
cd metal
cat BUILD.gn| sed -e 's#"QuartzCore.framework",#"QuartzCore.framework",\'$'\n        "CoreServices.framework",#g'  > BUILD.gn.tmp && mv -fv BUILD.gn.tmp BUILD.gn
popd
mkdir -pv out/release && pushd out/release
curl -OJ https://gist.githubusercontent.com/Wowfunhappy/0fcc5f6aab77794e9decbd8e7f4d4469/raw/26d7f50eece368c58fb4764cb43d9be0d4963e6e/args.gn
popd
pushd ../clang-master && echo "clang_base_path=\"`pwd`\"" >> ../chromium-legacy/out/release/args.gn
popd
cd src
gn gen ../out/release
time ninja -C ../out/release chrome
open -R ../out/release/Chromium.app

driver_utils_mac.mm

//
// Copyright 2019 The ANGLE Project Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//

// driver_utils_mac.mm : provides mac-specific information about current driver.

#include "libANGLE/renderer/driver_utils.h"

#import <Foundation/Foundation.h>

namespace rx
{

OSVersion GetMacOSVersion()
{
    OSVersion result;
    if (@available(macOS 10.10, *)) {
      NSOperatingSystemVersion version = [[NSProcessInfo processInfo] operatingSystemVersion];
      result.majorVersion              = static_cast<int>(version.majorVersion);
      result.minorVersion              = static_cast<int>(version.minorVersion);
      result.patchVersion              = static_cast<int>(version.patchVersion);
    } else {
      extern OSErr Gestalt(OSType selector, SInt32 *response) __attribute__((weak_import, weak));
      ::Gestalt(gestaltSystemVersionMajor, reinterpret_cast<SInt32*>(&result.majorVersion));
      ::Gestalt(gestaltSystemVersionMinor, reinterpret_cast<SInt32*>(&result.minorVersion));
      ::Gestalt(gestaltSystemVersionBugFix, reinterpret_cast<SInt32*>(&result.patchVersion));
    }
    return result;
}

}

NSArray.h

// Append below to before NS_ASSUME_NONNULL_END of NSArray.h

@implementation NSArray (NSExtendedArray)

- (id) objectAtIndexedSubscript: (NSUInteger)index
{
	return [self objectAtIndex: index];
}

@end

@implementation NSMutableArray (NSExtendedMutableArray)

 - (void) setObject:(id)obj atIndexedSubscript:(NSUInteger)index{
    if (index < self.count){
        if (obj)
            [self replaceObjectAtIndex:index withObject:obj];
        else
            [self removeObjectAtIndex:index];
    } else {
        [self addObject:obj];
    }
}

@end

API_AVAILABLE(macosx(10.15), ios(13.0), watchos(6.0), tvos(13.0))
NS_SWIFT_UNAVAILABLE("NSMutableArray diffing methods are not available in Swift")
@interface NSMutableArray<ObjectType> (NSMutableArrayDiffing)

- (void)applyDifference:(NSOrderedCollectionDifference<ObjectType> *)difference;

@end

NSDictionary.h

// Append below to before NS_ASSUME_NONNULL_END of NSDictionary.h

@implementation NSDictionary (NSExtendedDictionary)

- (nullable id)objectForKeyedSubscript:(id)key
{
	return [self objectForKey: key];
}

@end

@implementation NSMutableDictionary (NSExtendedMutableDictionary)

- (void) setObject: (nullable id)anObject forKeyedSubscript: (id)aKey
{
	[self setObject: anObject forKey: aKey];
}

- (nullable id) objectForKeyedSubscript: (id)aKey
{
        return [self objectForKey: aKey];
}

@end

sp_mut.cc

#include <__config>
#include <type_traits>
#include <typeinfo>
#include <cstddef>
#include <cstdint>
#include <new>
#include <utility>
#include <functional>
#include <limits>
#include <iterator>
#include <__functional_base>
#include <iosfwd>
#include <tuple>
#include <stdexcept>
#include <cstring>
#if !defined(_LIBCPP_HAS_NO_ATOMIC_HEADER)
#  include <atomic>
#endif
#include <version>

_LIBCPP_PUSH_MACROS
#include <__undef_macros>

_LIBCPP_BEGIN_NAMESPACE_STD

_LIBCPP_AVAILABILITY_ATOMIC_SHARED_PTR
__sp_mut& __get_sp_mut(const void*);

_LIBCPP_SAFE_STATIC static const std::size_t __sp_mut_count = 16;
_LIBCPP_SAFE_STATIC static __libcpp_mutex_t mut_back[__sp_mut_count] =
{
    _LIBCPP_MUTEX_INITIALIZER, _LIBCPP_MUTEX_INITIALIZER, _LIBCPP_MUTEX_INITIALIZER, _LIBCPP_MUTEX_INITIALIZER,
    _LIBCPP_MUTEX_INITIALIZER, _LIBCPP_MUTEX_INITIALIZER, _LIBCPP_MUTEX_INITIALIZER, _LIBCPP_MUTEX_INITIALIZER,
    _LIBCPP_MUTEX_INITIALIZER, _LIBCPP_MUTEX_INITIALIZER, _LIBCPP_MUTEX_INITIALIZER, _LIBCPP_MUTEX_INITIALIZER,
    _LIBCPP_MUTEX_INITIALIZER, _LIBCPP_MUTEX_INITIALIZER, _LIBCPP_MUTEX_INITIALIZER, _LIBCPP_MUTEX_INITIALIZER
};

_LIBCPP_CONSTEXPR __sp_mut::__sp_mut(void* p) _NOEXCEPT
   : __lx(p)
{
}

void
__sp_mut::lock() _NOEXCEPT
{
    auto m = static_cast<__libcpp_mutex_t*>(__lx);
    unsigned count = 0;
    while (!__libcpp_mutex_trylock(m))
    {
        if (++count > 16)
        {
            __libcpp_mutex_lock(m);
            break;
        }
        __libcpp_thread_yield();
    }
}

void
__sp_mut::unlock() _NOEXCEPT
{
    __libcpp_mutex_unlock(static_cast<__libcpp_mutex_t*>(__lx));
}

__sp_mut&
__get_sp_mut(const void* p)
{
    static __sp_mut muts[__sp_mut_count]
    {
        &mut_back[ 0], &mut_back[ 1], &mut_back[ 2], &mut_back[ 3],
        &mut_back[ 4], &mut_back[ 5], &mut_back[ 6], &mut_back[ 7],
        &mut_back[ 8], &mut_back[ 9], &mut_back[10], &mut_back[11],
        &mut_back[12], &mut_back[13], &mut_back[14], &mut_back[15]
    };
    return muts[hash<const void*>()(p) & (__sp_mut_count-1)];
}


_LIBCPP_END_NAMESPACE_STD

_LIBCPP_POP_MACROS

#if defined(_LIBCPP_HAS_PARALLEL_ALGORITHMS) && _LIBCPP_STD_VER >= 17
#   include <__pstl_memory>
#endif