git clone https://chromium.googlesource.com/chromium/tools/depot_tools.git
export PATH="/path/to/depot_tools:$PATH"
# for FISH set -U fish_user_paths /home/kar/p/build/depot_tools $fish_user_paths && source ~/.config/fish/config.fish
#git python3 curl is needed
mkdir chromium && cd chromium
fetch chromium  # this will get the chromium & it takes time
cd src
./build/install-build-deps.sh
./build/install-build-deps-arch.py  # for arch linux i have created
# Basic installation 
./build/install-build-deps-arch.py # With 32-bit libraries and ARM cross-compilation 
./build/install-build-deps-arch.py --lib32 --arm # Non-interactive installation 
./build/install-build-deps-arch.py --no-prompt # Using paru instead of yay for AUR packages 
./build/install-build-deps-arch.py --aur-helper paru 
# Quick check without installing 
./install-build-deps-arch.py --quick-check

on windows python build\install-build-deps.py
gn gen out/Default  #generate build files
autoninja -C out/Default chrome  #starts the build
customize Build Configuration Options.
gn gen out/Custom --args='
  is_debug=false
  symbol_level=1
  enable_nacl=false
  remove_webcore_debug_symbols=true
  proprietary_codecs=true
  ffmpeg_branding="Chrome"
'

the build setup script for arch linux: https://git.siliconpin.com/topic/chromium-build/src/branch/main/install-build-deps-arch.py

Building the Chromium browser from source involves several steps, including setting up your environment, obtaining the source code, and compiling the project. This process can be resource-intensive, requiring a powerful machine with ample RAM and disk space.

1. System Requirements:

An x86-64 machine with at least 8GB of RAM (16GB+ recommended).

At least 100GB of free disk space.

Git and Python v3.9+ installed. 

2. Install Depot Tools:

Download depot_tools from the Chromium website. ( git clone https://chromium.googlesource.com/chromium/tools/depot_tools )

Extract the archive to a designated location (e.g., C:\chromium\depot_tools on Windows or ~/depot_tools on Linux/macOS).

Add the depot_tools directory to your system's PATH environment variable, ensuring it takes precedence over any existing Python installations.

On Windows, set the environment variable DEPOT_TOOLS_WIN_TOOLCHAIN to 0.

3. Get the Chromium Source Code:

Create a directory for your Chromium checkout (e.g., C:\chromium\src or ~/chromium/src).

Navigate to this directory in your terminal or command prompt.

Run the following command to fetch the source code:

Code

    gclient config --name src https://chromium.googlesource.com/chromium/src.git
    gclient sync

This command can take a significant amount of time, depending on your internet connection.

4. Install Build Dependencies (Linux/macOS):

Navigate to the src directory of your Chromium checkout.

Run the appropriate script to install build dependencies for your operating system:

Code

    build/install-build-deps.sh  # For Linux
    # Follow instructions in docs/mac_build_instructions.md for macOS

5. Generate Build Files:

Navigate to the src directory.

Generate the build files using gn gen. You can create a build directory with a custom name and arguments:

Code

    gn gen out/Default

Replace Default with a name of your choice. You can add build arguments for release settings, specific features, etc., by running gn args out/Default and editing the configuration.

6. Compile Chromium:

Navigate to the src directory and Compile Chromium using autoninja.

Code

    autoninja -C out/Default chrome

Replace Default with your chosen build directory name. This step will take a considerable amount of time and resources.

7. Run Your Custom Browser:

Once the compilation is complete, the Chromium executable will be located within your build directory (e.g., out/Default/chrome.exe on Windows or out/Default/Chromium.app on macOS).

You can then run this executable to launch your custom-built Chromium browser.

autoninja -C out/Default chrome offline mode ninja: Entering directory `out/Default' 1.45s load siso config pre:0 local:4474 remote:0 13.8/s

explain pre:0 local:4474 remote:0 13.8/s

Ans:

This output is from Siso (Simple Isolated Builds), which is Google's distributed build system used in Chromium. Let me break down what each part means:

Build Status Breakdown:

pre:0

Preprocessor jobs: Number of preprocessing tasks (like header dependency analysis)

0 means no preprocessing jobs are currently running

local:4474

Local compilation jobs: Number of compilation tasks being executed on your local machine

4474 means 4,474 compilation units have been processed locally so far

remote:0

Remote compilation jobs: Number of tasks sent to remote build servers (like Goma or RBE - Remote Build Execution)

0 means no remote compilation is happening

13.8/s

Throughput rate: Number of compilation units being processed per second

Your build is processing about 13.8 files per second

What This Tells You:

You're building entirely locally - no distributed compilation is being used

Good progress - 4,474 files have been compiled already

Reasonable speed - 13.8 files/second is decent for local compilation

Offline mode - As indicated at the top, you're not using any remote build acceleration

Context:

Chromium has thousands of source files, so seeing 4,474+ compilation units is normal. A full Chrome build can involve compiling 10,000+ files, so you're making good progress through the build process.

The build system is efficiently parallelizing the work across your CPU cores, which is why you're seeing a steady throughput rate.

after successful build, out/Default is ~40gb and chrome file is 1.5gb

Linux: ./out/Default/chrome

MacOS: ./out/Default/Chromium.app/Contents/MacOS/Chromium

Windows: ./out/Default/chrome.exe

autoninja -C out/Default content_shell # Minimal browser for testing

autoninja -C out/Default chrome_sandbox # Security sandbox

#Clean rebuild

gn clean out/Default

autoninja -C out/Default chrome

#Debug Build

gn gen out/Debug --args='is_debug=true'

autoninja -C out/Debug chrome

#Release Build

gn gen out/Release --args='is_debug=false is_official_build=true'

autoninja -C out/Release chrome