大体含义是，创建多个 Service 类提前注册，分别命名为sandbox， 然后对于更细节的子进程逻辑实现是通过反射获取的内核代码
通过下面的demo可以看出，chromium的子进程数最大是多少
/**
* Delegates service calls to the chrome service implementation.
*/
@SuppressWarnings("JavadocType")
public abstract class ChildProcessService extends Service {
private IChildProcessService mImpl;
public ChildProcessService() {}
@Override
public void onCreate() {
super.onCreate();
try {
Context appContext = getApplicationContext();
Context remoteContext = WebLayer.getOrCreateRemoteContext(appContext);
if (WebLayer.getSupportedMajorVersion(appContext) < 81) {
mImpl = IChildProcessService.Stub.asInterface(
(IBinder) remoteContext.getClassLoader()
.loadClass("org.chromium.weblayer_private.ChildProcessServiceImpl")
.getMethod("create", Service.class, Context.class)
.invoke(null, this, appContext));
} else {
mImpl = IChildProcessService.Stub.asInterface(
(IBinder) remoteContext.getClassLoader()
.loadClass("org.chromium.weblayer_private.ChildProcessServiceImpl")
.getMethod("create", Service.class, Context.class, Context.class)
.invoke(null, this, appContext, remoteContext));
}
mImpl.onCreate();
} catch (Exception e) {
throw new APICallException(e);
}
}
@Override
public void onDestroy() {
super.onDestroy();
try {
mImpl.onDestroy();
mImpl = null;
} catch (RemoteException e) {
throw new APICallException(e);
}
}
@Override
public IBinder onBind(Intent intent) {
try {
return ObjectWrapper.unwrap(mImpl.onBind(ObjectWrapper.wrap(intent)), IBinder.class);
} catch (RemoteException e) {
throw new APICallException(e);
}
}
public static class Privileged extends ChildProcessService {}
public static final class Privileged0 extends Privileged {}
public static final class Privileged1 extends Privileged {}
public static final class Privileged2 extends Privileged {}
public static final class Privileged3 extends Privileged {}
public static final class Privileged4 extends Privileged {}
public static class Sandboxed extends ChildProcessService {}
public static final class Sandboxed0 extends Sandboxed {}
// ... 省略大部分模板代码
public static final class Sandboxed39 extends Sandboxed {}
}