Ninja is a build system written with the specific goal of improving the edit-compile cycle time. It is used by default everywhere except when building for iOS.
Ninja behaves very similar to Make -- the major feature is that it starts building files nearly instantly. (It has a number of minor user interface improvements to make as well.)
Read more about Ninja at the Ninja home page.
Ninja is included in depot_tools so there's nothing to install.
To build Chrome:
cd /path/to/chrome/src ninja -C out/Debug chrome
Specify out/Release for a release build. I recommend setting up an alias so that you don't need to type out that build directory path.
If you want to build all targets, use ninja -C out/Debug all. It‘s faster to build only the target you’re working on, like chrome or unit_tests.
Identical to Linux, just make sure OS=android is in your GYP_DEFINES. You want to build one of the apk targets, e.g. content_shell_apk.
Similar to Linux. It uses MSVS's cl.exe, link.exe, etc. so you still need to have VS installed. To use it, open cmd.exe, go to your chrome checkout, and run:
set GYP_DEFINES=component=shared_library python build\gyp_chromium ninja -C out\Debug chrome.exe
component=shared_library is optional but recommended for faster links.
You can also set GYP_GENERATORS=ninja,msvs-ninja to get both VS projects generated if you want to use VS just to browse/edit (but then gyp takes twice as long to run).
If you‘re using Express or the Windows SDK by itself (rather than using a Visual Studio install), you’ll need to run from a vcvarsall command prompt.
Miss VS for debugging?
devenv.com /debugexe chrome.exe --my-great-args "go here" --single-process etc
Miss Xcode for debugging? Read http://dev.chromium.org/developers/debugging-on-os-x/building-with-ninja-debugging-with-xcode
That is, building with just the WinDDK. This is documented in the regular build instructions.
Pass a flag like -k3 to make Ninja build until it hits three errors instead of stopping at the first.
Pass a flag like -j8 to use 8 parallel processes, or -j1 to compile just one at a time (helpful if you're getting weird compiler errors). By default Ninja tries to use all your processors.
There are more options. Run ninja --help to see them all.
You can write a specific build config to a specific output directory via the -G flags to gyp. Here's an example from jamesr: build/gyp_chromium -Gconfig=Release -Goutput_dir=out_profiling -Dprofiling=1 -Dlinux_fpic=0
If you encounter any problems, please file a bug at http://crbug.com/new with label ninja and cc thakis@ or scottmg@. Assume that it is a bug in Ninja before you bother anyone about e.g. link problems.