You can create a debug build of Electron by following build instructions for macOS. The bootstrap process will download Release version of libchromiumcontent by default, so you will not be able to step through the Chromium source.
If you want to debug and step through libchromiumcontent, you will have to run the
bootsrap script with the
$ cd electron $ ./script/bootstrap.py -v --build_debug_libcc
This can take a significant amount of time depending on build machine as it has to build all of the libchromium source.
Once, the lib is built, create a symlink to the built directory under download
ln -s vendor/libchromiumcontent/dist/main/shared_library vendor/download/libchromiumcontent/shared_library
Electron debug builds will use this shared library to link against.
$ ./script/build.py -c D --libcc
This will build debug Electron with debug version of libchromiumcontent.
Run the update script with the --xcode argument.
$ ./script/update.py --xcode
This will generate the electron.ninjs.xcworkspace. You will have to open this workspace to set breakpoints and inspect.
Launch Electron app after build. You can now open the xcode workspace created above and attach to the Electron process through the Debug > Attach To Process > Electron debug menu. [Note: If you want to debug the renderer process, you need to attach to the Electron Helper as well.]
You can now set breakpoints in any of the indexed files. However, you will not be able to set breakpoints directly in the Chromium source. To set break points in the Chromium source, you can choose Debug > Breakpoints > Create Symbolic Breakpoint and set any function name as the symbol. This will set the breakpoint for all functions with that name, from all the classes if there are more than one. You can also do this step of setting break points prior to attaching the debugger, however, actual breakpoints for symbolic breakpoint functions may not show up until the debugger is attached to the app.