code: private void applyCompilerDefaultValueOverrides(
        Map<String, TweakInfo> tweakInfos) {
      for (Entry<String, Node> entry : compilerDefaultValueOverrides.entrySet()) {
        String tweakId = entry.getKey();
        TweakInfo tweakInfo = tweakInfos.get(tweakId);
        if (tweakInfo == null) {
          compiler.report(JSError.make(UNKNOWN_TWEAK_WARNING, tweakId));
        } else {
          TweakFunction registerFunc = tweakInfo.registerCall.tweakFunc;
          Node value = entry.getValue();
          if (!registerFunc.isValidNodeType(value.getToken())) {
            compiler.report(JSError.make(INVALID_TWEAK_DEFAULT_VALUE_WARNING,
                tweakId, registerFunc.getName(),
                registerFunc.getExpectedTypeName()));
          } else {
            tweakInfo.defaultValueNode = value;
          }
        }
      }
    }
docs: Sets the default values of tweaks based on compiler options.