Dumpsys support for IncrementalService.

Test: atest PackageManagerShellCommandTest
Test: adb shell dumpsys incremental
Bug: b/136132412 b/133435829
Change-Id: I8a91eddb850c68da87f56a82ca14fdf9ac5d3ce5
diff --git a/services/incremental/IncrementalService.h b/services/incremental/IncrementalService.h
index ca5e4db..8280287 100644
--- a/services/incremental/IncrementalService.h
+++ b/services/incremental/IncrementalService.h
@@ -90,6 +90,8 @@
         return idFromMetadata({(const uint8_t*)metadata.data(), metadata.size()});
     }
 
+    void onDump(int fd);
+
     std::optional<std::future<void>> onSystemReady();
 
     StorageId createStorage(std::string_view mountPoint,