Move old_chromeos_build_instructions.md to chromeos_build_instructions.md
Also make small tweaks
Bug: 800837
Change-Id: I747c286ddd4191a09a436b647958df1f9875969c
Reviewed-on: https://chromium-review.googlesource.com/861043
Commit-Queue: Jacob Dufault <[email protected]>
Reviewed-by: Steven Bennetts <[email protected]>
Cr-Commit-Position: refs/heads/master@{#529092}diff --git a/docs/chromeos_build_instructions.md b/docs/chromeos_build_instructions.md
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+# Chrome OS Build Instructions (Chromium OS on Linux)
+
+Chromium on Chromium OS is built from a mix of code sourced from Chromium
+on Linux and Chromium on Windows. Much of the user interface code is
+shared with Chromium on Windows.
+
+If you make changes to Chromium on Windows, they may affect Chromium
+on Chromium OS. Fortunately to test the effects of your changes you
+don't need to build all of Chromium OS, you can just build Chromium for
+Chromium OS directly on Linux.
+
+First, follow the [normal Linux build
+instructions](https://chromium.googlesource.com/chromium/src/+/master/docs/linux_build_instructions.md)
+as usual to get a Chromium checkout.
+
+## Building and running Chromium with Chromium OS UI on your local machine
+
+If you plan to test the Chromium build on your dev machine and not a
+Chromium OS device, run the following in your chromium checkout:
+
+ $ gn gen out/Default --args='target_os="chromeos"'
+ $ ninja -C out/Default -j32
+
+NOTE: You may wish to replace 'Default' with something like 'Cros' if
+you switch back and forth between Linux and Chromium OS builds, or 'Debug'
+if you want to differentiate between Debug and Release builds (see below)
+or DebugCros or whatever you like.
+
+NOTE: If using goma increase -j32 (which controls parallelization) to something
+higher, 500 or 1000. Consider adding `-l20` which prevents ninja from starting
+jobs if the load average is too high - this prevents system hangs when using
+-j1000 when goma is down.
+
+See [GN Build Configuration](https://www.chromium.org/developers/gn-build-configuration)
+for more information about configuring your build.
+
+Some additional options you may wish to set by passing in `--args` to `gn gen`
+or running `gn args out/Default`:
+
+ is_component_build = true
+ use_goma = true
+ is_debug = false # Release build, significantly faster
+ dcheck_always_on = true # Enable DCHECK (with is_debug = false)
+
+ # Set the following true to create a Chrome (instead of Chromium) build.
+ is_official_build = false
+ is_chrome_branded = false
+
+## Notes
+
+The Chromium OS build requires a functioning GL so if you plan on
+testing it through Chromium Remote Desktop you might face drawing
+problems (e.g. Aura window not painting anything). Possible remedies:
+
+* `--ui-enable-software-compositing --ui-disable-threaded-compositing`
+* `--use-gl=osmesa`, but it's ultra slow, and you'll have to build osmesa
+ yourself.
+
+To more closely match the UI used on devices, you can install fonts used
+by Chrome OS, such as Roboto, on your Linux distro.
+
+To specify a logged in user:
+
+* For first run, add the following options to the command line:
+ `--user-data-dir=/tmp/chrome --login-manager`
+* Go through the out-of-the-box UX and sign in as
+ **[email protected]**.
+* For subsequent runs, add the following to the command line:
+ `--user-data-dir=/tmp/chrome [email protected]`
+* To run in guest mode instantly, you can run add the arguments:
+ `--user-data-dir=/tmp/chrome --bwsi --incognito --login-user='$guest'
+ --login-profile=user`
+
+Signing in as a specific user is useful for debugging features like sync
+that require a logged in user.
+
+## Compile Chromium for a Chromium OS device using the Chromium OS SDK
+
+See [Building Chromium for a Chromium OS device](https://www.chromium.org/chromium-os/how-tos-and-troubleshooting/building-chromium-browser)
+for information about building and testing chromium for Chromium OS.
