Add runInBackground Interface method

Summary:
Add support for plugins to opt in to background for android.
This diff does the following
- Adds a method `runInBackground` in java interface of `FlipperPlugin`
- Make the network plugin opt in to run in background

Reviewed By: danielbuechele

Differential Revision: D10360033

fbshipit-source-id: b31c7550d00b760b7033c150232e3925b6272d24

android/src/main/cpp/sonar.cpp

@@ -198,6 +198,11 @@ class JFlipperPlugin : public jni::JavaClass<JFlipperPlugin> {
     static const auto method = javaClassStatic()->getMethod<void()>("onDisconnect");
     method(self());
   }
+
+    bool runInBackground() {
+        static const auto method = javaClassStatic()->getMethod<jboolean()>("runInBackground");
+        return method(self()) == JNI_TRUE;
+    }
 };
 
 class JFlipperStateUpdateListener : public jni::JavaClass<JFlipperStateUpdateListener> {
@@ -247,6 +252,10 @@ class JFlipperPluginWrapper : public FlipperPlugin {
     jplugin->didDisconnect();
   }
 
+    virtual bool runInBackground() override {
+        return jplugin->runInBackground();
+    }
+
   JFlipperPluginWrapper(jni::global_ref<JFlipperPlugin> plugin): jplugin(plugin) {}
 };