Introduction

The policy for adding new (major) features to WebKit is:

• Send email to webkit-dev describing the feature and linking to the tracking bug.
• If necessary, add an ENABLE flag for the feature.

How to add an ENABLE flag

By adding a build definition for ENABLE_FEATURE it allows code/preprocessor to test using ENABLE(FEATURE). You'll need to edit at least the following files:

• Source/JavaScriptCore/Configurations/FeatureDefines.xcconfig
• Source/WebCore/Configurations/FeatureDefines.xcconfig
• Source/WebKit/mac/Configurations/FeatureDefines.xcconfig
• Source/WebKit2/Configurations/FeatureDefines.xcconfig
• Source/autotools/SetupWebKitFeatures.m4
• Source/WebKit/chromium/features.gypi
• Source/cmake/WebKitFeatures.cmake
• Source/cmakeconfig.h.cmake
• Source/WTF/wtf/FeatureDefines.h
• Tools/Scripts/webkitperl/FeatureList.pm
• Tools/qmake/mkspecs/features/features.pri
• WebKitLibraries/win/tools/vsprops/FeatureDefines.vsprops
• WebKitLibraries/win/tools/vsprops/FeatureDefinesCairo.vsprops

Note that only defines the feature. To turn the feature on, you'll need to edit the build configurations for each port. (TODO: page describing where each configuration is?)

After adding a feature, please add it to the list in the wiki

Activating a feature for CMAKE based ports

• Edit Source/cmake/Options<Port>.cmake, e.g. OptionsEfl.cmake and set a default value for this feature.
• Edit Tools/Scripts/webkitperl/FeatureList.pm to default enable this for the same port, e.g add a isPort() statement to the default setting assignment.

Activating a feature for Autotools based ports

At the moment only the GTK port is using this build system

There are two files that control features for GTK+:

• Source/autotools/SetupWebKitFeatures.m4: This file controls the features enabled for WebKitGTK+ release builds -- the equivalent of production builds. In general, new and unstable features should be disabled here.
• Tools/Scripts/webkitperl/FeatureList.pm: This file controls the features enabled for WebKitGTK+ development builds. We like to enable things early here to get test coverage as soon as possible.