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/java/com/facebook/flipper/core/FlipperPlugin.java

@@ -34,4 +34,9 @@ public interface FlipperPlugin {
    * longer valid. Do not try to use the connection in or after this method has been called.
    */
   void onDisconnect() throws Exception;
+
+  /**
+   Returns true if the plugin is meant to be run in background too, otherwise it returns false.
+   */
+  boolean runInBackground();
 }

android/src/main/java/com/facebook/flipper/plugins/common/BufferingFlipperPlugin.java

@@ -37,6 +37,11 @@ public abstract class BufferingFlipperPlugin implements FlipperPlugin {
     mConnection = null;
   }
 
+  @Override
+  public boolean runInBackground() {
+    return true;
+  }
+
   public synchronized FlipperConnection getConnection() {
     return mConnection;
   }

android/src/main/java/com/facebook/flipper/plugins/console/ConsoleFlipperPlugin.java

@@ -31,4 +31,9 @@ public class ConsoleFlipperPlugin implements FlipperPlugin {
   }
 
   public void onDisconnect() throws Exception {}
+
+  @Override
+  public boolean runInBackground() {
+    return false;
+  }
 }

android/src/main/java/com/facebook/flipper/plugins/inspector/InspectorFlipperPlugin.java

@@ -171,6 +171,11 @@ public class InspectorFlipperPlugin implements FlipperPlugin {
     mConnection = null;
   }
 
+  @Override
+  public boolean runInBackground() {
+    return false;
+  }
+
   final FlipperReceiver mShouldShowLithoAccessibilitySettings =
       new MainThreadFlipperReceiver(mConnection) {
         @Override

android/src/main/java/com/facebook/flipper/plugins/leakcanary/LeakCanaryFlipperPlugin.java

@@ -57,6 +57,11 @@ public class LeakCanaryFlipperPlugin implements FlipperPlugin {
     mConnection = null;
   }
 
+  @Override
+  public boolean runInBackground() {
+    return false;
+  }
+
   private void sendLeakList() {
     if (mConnection != null) {
       JSONObject obj = new JSONObject();

android/src/main/java/com/facebook/flipper/plugins/sandbox/SandboxFlipperPlugin.java

@@ -68,4 +68,9 @@ public class SandboxFlipperPlugin implements FlipperPlugin {
 
   @Override
   public void onDisconnect() {}
+
+    @Override
+    public boolean runInBackground() {
+        return false;
+    }
 }

android/src/main/java/com/facebook/flipper/plugins/sharedpreferences/SharedPreferencesFlipperPlugin.java

@@ -200,6 +200,11 @@ public class SharedPreferencesFlipperPlugin implements FlipperPlugin {
     mConnection = null;
   }
 
+  @Override
+  public boolean runInBackground() {
+    return false;
+  }
+
   public static class SharedPreferencesDescriptor {
     public final String name;
     public final int mode;