[incremental] expose duration since oldest pending read

As requested by go/incremental-disablement-metrics, we will expose the
duration since oldest pending read as part of the crash/ANR metrics.
This is the first step that exposes the value to Incremental Service.

BUG: 180951530
Test: unit test
Change-Id: Ic67460072556ef01780a1794b40924ca2092060d
diff --git a/services/incremental/BinderIncrementalService.h b/services/incremental/BinderIncrementalService.h
index 740c542..ebb23dc 100644
--- a/services/incremental/BinderIncrementalService.h
+++ b/services/incremental/BinderIncrementalService.h
@@ -18,6 +18,7 @@
 
 #include <binder/BinderService.h>
 #include <binder/IServiceManager.h>
+#include <binder/PersistableBundle.h>
 #include <jni.h>
 
 #include "IncrementalService.h"
@@ -97,6 +98,8 @@
             const ::android::os::incremental::StorageHealthCheckParams& healthCheckParams,
             const ::android::sp<IStorageHealthListener>& healthListener, bool* _aidl_return) final;
     binder::Status unregisterStorageHealthListener(int32_t storageId) final;
+    binder::Status getMetrics(int32_t storageId,
+                              android::os::PersistableBundle* _aidl_return) final;
 
 private:
     android::incremental::IncrementalService mImpl;