官方地址:Checking out and building Chromium for iOS
记录遇到的问题:

1. 在Setting up the build第一步执行setup-gn.py脚本
   在chromium/src路径下执行命令:

vpython ios/build/tools/setup-gn.py

遇到错误:
xcode-select: error: tool 'xcodebuild' requires Xcode, but active developer directory '/Library/Developer/CommandLineTools' is a command line tools instance
解决方案:

sudo xcode-select -s /Applications/Xcode.app/Contents/Developer

2. xcode的command+r运行阶段:
   ERROR at //build/config/ios/ios_sdk.gni:100:21: Script returned non-zero exit code.
   删除chromium/src/out文件夹,重新执行vpython ios/build/tools/setup-gn.py,完成之后用
   命令autoninja -C out/Debug-iphonesimulator gn_all build一下项目看看没问题再用xcode(理论上直接用xcode就可以,迷信做法)