FocusResolver: Clean up focus requests and results when a display is removed

Prevents FocusResolver from leaking focus requests and results as
displays are added and removed.

Test: atest inputflinger_tests
Fixes: 188008394
Change-Id: I635b9becf91056fd540ab9d9546dd67a09324fc6
diff --git a/services/inputflinger/dispatcher/FocusResolver.h b/services/inputflinger/dispatcher/FocusResolver.h
index dc5eeeb..afe16b3 100644
--- a/services/inputflinger/dispatcher/FocusResolver.h
+++ b/services/inputflinger/dispatcher/FocusResolver.h
@@ -62,6 +62,9 @@
     std::optional<FocusResolver::FocusChanges> setFocusedWindow(
             const FocusRequest& request, const std::vector<sp<InputWindowHandle>>& windows);
 
+    // Display has been removed from the system, clean up old references.
+    void displayRemoved(int32_t displayId);
+
     // exposed for debugging
     bool hasFocusedWindowTokens() const { return !mFocusedWindowTokenByDisplay.empty(); }
     std::string dumpFocusedWindows() const;