Remove support for Android API < 23 in DebugOverlayController

Summary:
Since minsdk version was increased to 23, we are deleting code using Android APIs < 23 for class DebugOverlayController

chnagelog: [Android][Breaking] Remove support for Android API < 23 in DebugOverlayController

Differential Revision: D48545520

fbshipit-source-id: 3f69e2703acb4fbd3935ca44680634d1ce452f27

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

@@ -14,7 +14,6 @@
 import android.content.pm.PackageManager;
 import android.graphics.PixelFormat;
 import android.net.Uri;
-import android.os.Build;
 import android.provider.Settings;
 import android.view.WindowManager;
 import android.widget.FrameLayout;
@@ -31,33 +30,29 @@
 /* package */ class DebugOverlayController {
 
   public static void requestPermission(Context context) {
-    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
-      // Get permission to show debug overlay in dev builds.
-      if (!Settings.canDrawOverlays(context)) {
-        Intent intent =
-            new Intent(
-                Settings.ACTION_MANAGE_OVERLAY_PERMISSION,
-                Uri.parse("package:" + context.getPackageName()));
-        intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
-        FLog.w(
-            ReactConstants.TAG,
-            "Overlay permissions needs to be granted in order for react native apps to run in dev mode");
-        if (canHandleIntent(context, intent)) {
-          context.startActivity(intent);
-        }
+    // Get permission to show debug overlay in dev builds.
+    if (!Settings.canDrawOverlays(context)) {
+      Intent intent =
+          new Intent(
+              Settings.ACTION_MANAGE_OVERLAY_PERMISSION,
+              Uri.parse("package:" + context.getPackageName()));
+      intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
+      FLog.w(
+          ReactConstants.TAG,
+          "Overlay permissions needs to be granted in order for react native apps to run in dev mode");
+      if (canHandleIntent(context, intent)) {
+        context.startActivity(intent);
       }
     }
   }
 
   private static boolean permissionCheck(Context context) {
-    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
-      // Get permission to show debug overlay in dev builds.
-      if (!Settings.canDrawOverlays(context)) {
-        // overlay permission not yet granted
-        return false;
-      } else {
-        return true;
-      }
+    // Get permission to show debug overlay in dev builds.
+    if (!Settings.canDrawOverlays(context)) {
+      // overlay permission not yet granted
+      return false;
+    } else {
+      return true;
     }
     // on pre-M devices permission needs to be specified in manifest
     return hasPermission(context, Manifest.permission.SYSTEM_ALERT_WINDOW);