Passing current activity while creating react instance manager

Reviewed By: astreet

Differential Revision: D3236602

fb-gh-sync-id: efbac8f0d8c770f2edf6fb447498e650302d98c7
fbshipit-source-id: efbac8f0d8c770f2edf6fb447498e650302d98c7

ReactAndroid/src/main/java/com/facebook/react/ReactInstanceManager.java

@@ -186,6 +186,8 @@ public abstract class ReactInstanceManager {
     protected @Nullable UIImplementationProvider mUIImplementationProvider;
     protected @Nullable NativeModuleCallExceptionHandler mNativeModuleCallExceptionHandler;
     protected @Nullable JSCConfig mJSCConfig;
+    protected @Nullable Activity mCurrentActivity;
+    protected @Nullable DefaultHardwareBackBtnHandler mDefaultHardwareBackBtnHandler;
 
     protected Builder() {
     }
@@ -250,6 +252,17 @@ public abstract class ReactInstanceManager {
       return this;
     }
 
+    public Builder setCurrentActivity(Activity activity) {
+      mCurrentActivity = activity;
+      return this;
+    }
+
+    public Builder setDefaultHardwareBackBtnHandler(
+        DefaultHardwareBackBtnHandler defaultHardwareBackBtnHandler) {
+      mDefaultHardwareBackBtnHandler = defaultHardwareBackBtnHandler;
+      return this;
+    }
+
     /**
      * When {@code true}, developer options such as JS reloading and debugging are enabled.
      * Note you still have to call {@link #showDevOptionsDialog} to show the dev menu,
@@ -289,6 +302,8 @@ public abstract class ReactInstanceManager {
      * Before calling {@code build}, the following must be called:
      * <ul>
      * <li> {@link #setApplication}
+     * <li> {@link #setCurrentActivity} if the activity has already resumed
+     * <li> {@link #setDefaultHardwareBackBtnHandler} if the activity has already resumed
      * <li> {@link #setJSBundleFile} or {@link #setJSMainModuleName}
      * </ul>
      */
@@ -310,6 +325,8 @@ public abstract class ReactInstanceManager {
           Assertions.assertNotNull(
               mApplication,
               "Application property has not been set with this builder"),
+          mCurrentActivity,
+          mDefaultHardwareBackBtnHandler,
           mJSBundleFile,
           mJSMainModuleName,
           mPackages,