• Getting the source code
• Installing depot_tools

For getting v8's source, first, update depot_tools by running:

$ gclient

After depot_tools is updated, the missing part is decide a place to save v8 (folder in your filesystem) and run fetch command:

mkdir /path/for/chromium/
cd /path/for/chromium/
fetch v8
cd v8
# Update third party deps of v8
gclient sync

Ok, let's be real, this could take like WHILE (hm, a looonnnggg one), so, be prepared to be patient.

References:

• Chromium docs
• V8 docs

The depot_tools are just tooling for git operations of the Chromium project.

Open a terminal, and move to the folder that depot_tools will be installed and clone the repo:

$ git clone https://chromium.googlesource.com/chromium/tools/depot_tools.git

After clonning the depot_tools repository (this is just for better development experience, optional), add the depot_tools to PATH:

$ export PATH=/path/to/depot_tools:$PATH