Fix Nullsafe FIXMEs for DebugOverlayController.java and mark nullsafe (#50064)

Summary:
Pull Request resolved: #50064

Gone trough all the FIXMEs added in the previous diff by the nullsafe tool, marked the class as nullsafe and ensured no remaining violations.

Changelog: [Android][Fixed] Made DebugOverlayController.java nullsafe

Reviewed By: mdvacca

Differential Revision: D71126394

fbshipit-source-id: 77bba33f4f14566e133fa9e9649631bcffa3f0c9

Author: GijsWeterings

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/devsupport/DebugOverlayController.java

@@ -18,6 +18,7 @@
 import android.widget.FrameLayout;
 import androidx.annotation.Nullable;
 import com.facebook.common.logging.FLog;
+import com.facebook.infer.annotation.Nullsafe;
 import com.facebook.react.bridge.ReactContext;
 import com.facebook.react.bridge.UiThreadUtil;
 import com.facebook.react.common.ReactConstants;
@@ -26,7 +27,8 @@
  * Helper class for controlling overlay view with FPS and JS FPS info that gets added directly
  * to @{link WindowManager} instance.
  */
-/* package */ class DebugOverlayController {
+/* package */ @Nullsafe(Nullsafe.Mode.LOCAL)
+class DebugOverlayController {
 
   public static void requestPermission(Context context) {
     // Get permission to show debug overlay in dev builds.
@@ -74,8 +76,7 @@ private static boolean hasPermission(Context context, String permission) {
 
   private static boolean canHandleIntent(Context context, Intent intent) {
     PackageManager packageManager = context.getPackageManager();
-    // NULLSAFE_FIXME[Parameter Not Nullable]
-    return intent.resolveActivity(packageManager) != null;
+    return packageManager != null && intent.resolveActivity(packageManager) != null;
   }
 
   private final WindowManager mWindowManager;