It's possible to build most parts of the codebase on a Linux or Mac host while targeting Windows. This document describes how to set that up, and current restrictions.
What does not work:
All other targets build fine (including chrome, browser_tests, ...).
Uses of .asm files have been stubbed out. As a result, some of Skia's software rendering fast paths are not present in cross builds, Crashpad cannot report crashes, and NaCl defaults to disabled and cannot be enabled in cross builds (.asm bug).
Tell gclient that you need Windows build dependencies by adding target_os = ['win'] to the end of your .gclient. (If you already have a target_os line in there, just add 'win' to the list.) e.g.
solutions = [
{
...
}
]
target_os = ['android', 'win']
gclient sync, follow instructions on screen.
If you're at Google, this will automatically download the Windows SDK for you. If this fails with an error: Please follow the instructions at https://www.chromium.org/developers/how-tos/build-instructions-windows then you may need to re-authenticate via:
cd path/to/chrome/src # Follow instructions, enter 0 as project id. download_from_google_storage --config
If you are not at Google, you‘ll have to figure out how to get the SDK, and you’ll need to put a JSON file describing the SDK layout in a certain location.
Add target_os = "win" to your args.gn. Then just build, e.g.
ninja -C out/gnwin base_unittests.exe
A convenient way to copy chrome over to a Windows box is to build the mini_installer target. Then, copy just mini_installer.exe over to the Windows box and run it to install the chrome you just built.
You can run the Windows binaries you built on swarming, like so:
tools/run_swarmed.py -C out/gnwin -t base_unittests [ --gtest_filter=... ]
See the contents of run_swarmed.py for how to do this manually.
There's a bot doing 64-bit release cross builds at https://ci.chromium.org/buildbot/chromium.clang/linux-win_cross-rel/ which also runs tests. You can look at it to get an idea of which tests pass in the cross build.