Chrome for iOS Instructions

You are building specifically for Chrome for iOS. Most of the time your changes will touch folders with /ios/ in their path e.g. the folder //ios/ at the root of the repository. We rarely have to make changes outside that scope but this can happen when the code to change is shared across platforms.

Source Files

Source files in Chrome for iOS are usually Objective-C++, so there are C++ classes and Objective-C classes interoperating often in the same file. File names use snake case and end with .h file extension for header files or .mm extension for source files. Class names use CamelCase.

If you need to create files, the following rules must be followed, unless stated otherwise.

• A class Foo must have foo.h as header file and foo.mm as source file.
• Unit test for class Foo must be implemented in a file foo_unittest.mm.
• EG tests for feature Bar must be implemented in a file bar_egtest.mm.

Output Directories

On iOS, the following output directories are often used.

• Debug-iphonesimulator - for a debug build running in iOS simulator.
• Debug-iphoneos - for a debug build running in iOS device.

See the content of //out/ for the full list of available output directories.

Build Targets

If you need to build, here is a list of targets often used on iOS.

• chrome - for the main Chrome app in iOS.
• ios_chrome_unittests - for unit tests inside //ios/chrome/.
• components_unittests - for unit tests inside //components/.
• ios_chrome_ui_eg2tests_module - for most EG tests.

If you need to build ios_chrome_ui_eg2tests_module EG tests, do the following.

autoninja --quiet -C out/Debug-iphonesimulator ios_chrome_ui_eg2tests_module

Running Unit Tests

To build and run unit tests inside //ios/chrome, use the ios/tools/run_unittests.py script.

# Run specific tests using gtest_filter
ios/tools/run_unittests.py --gtest_filter="ExampleTest1.*:ExampleTest2.*"

# Run tests on a specific device
ios/tools/run_unittests.py --gtest_filter="ExampleTest1.*" --device="iPhone 16 Pro"

# Run tests on a specific OS version
ios/tools/run_unittests.py --gtest_filter="ExampleTest1.*" --device="iPhone 15" --os="17.5"

Running EG Tests

To run EG tests, use the ios/tools/run_egtests.py script. This script handles building and running the tests on a simulator.

# Run a specific test case on the default simulator
ios/tools/run_egtests.py --tests=ExampleTestCase/testExample

# Run a test on a specific device
ios/tools/run_egtests.py --tests=ExampleTestCase/testExample --device="iPhone 16 Pro"

# Run a test on a specific device and OS version
ios/tools/run_egtests.py --tests=ExampleTestCase/testExample --device="iPhone 15" --os="17.5"