Added missing annotations to react

app/src/main/java/acr/browser/lightning/react/Action.java

@@ -1,5 +1,7 @@
 package acr.browser.lightning.react;
 
+import android.support.annotation.NonNull;
+
 public interface Action<T> {
-    void onSubscribe(Subscriber<T> subscriber);
+    void onSubscribe(@NonNull Subscriber<T> subscriber);
 }

app/src/main/java/acr/browser/lightning/react/Observable.java

@@ -18,12 +18,12 @@ import acr.browser.lightning.utils.Preconditions;
  */
 public class Observable<T> {
 
-    private Action<T> mAction;
+    @NonNull private Action<T> mAction;
     @Nullable private Executor mSubscriber;
     @Nullable private Executor mObserver;
-    private final Executor mDefault;
+    @NonNull private final Executor mDefault;
 
-    public Observable(Action<T> action) {
+    public Observable(@NonNull Action<T> action) {
         mAction = action;
         Looper looper = Looper.myLooper();
         Preconditions.checkNonNull(looper);

app/src/main/java/acr/browser/lightning/react/Schedulers.java

@@ -1,6 +1,7 @@
 package acr.browser.lightning.react;
 
 import android.os.Looper;
+import android.support.annotation.NonNull;
 
 import java.util.concurrent.Executor;
 import java.util.concurrent.Executors;
@@ -9,10 +10,12 @@ public class Schedulers {
     private static final Executor sWorker = Executors.newCachedThreadPool();
     private static final Executor sMain = new ThreadExecutor(Looper.getMainLooper());
 
+    @NonNull
     public static Executor worker() {
         return sWorker;
     }
 
+    @NonNull
     public static Executor main() {
         return sMain;
     }