Merge "Add logs for FragmentManager OnBackPressedCallback" into androidx-main

diff --git a/fragment/fragment/src/main/java/androidx/fragment/app/FragmentManager.java b/fragment/fragment/src/main/java/androidx/fragment/app/FragmentManager.java
index 5c393da..37ed965 100644
--- a/fragment/fragment/src/main/java/androidx/fragment/app/FragmentManager.java
+++ b/fragment/fragment/src/main/java/androidx/fragment/app/FragmentManager.java

@@ -730,8 +730,15 @@
         // This FragmentManager needs to have a back stack for this to be enabled
         // And the parent fragment, if it exists, needs to be the primary navigation
         // fragment.
-        mOnBackPressedCallback.setEnabled(getBackStackEntryCount() > 0
-                && isPrimaryNavigation(mParent));
+        boolean isEnabled = getBackStackEntryCount() > 0
+                && isPrimaryNavigation(mParent);
+        if (FragmentManager.isLoggingEnabled(Log.DEBUG)) {
+            Log.d(FragmentManager.TAG,
+                    "OnBackPressedCallback for FragmentManager " + this + " enabled state is "
+                            + isEnabled
+            );
+        }
+        mOnBackPressedCallback.setEnabled(isEnabled);
     }
 
     /**