Add flag with param for sharing device expiration in hours.

Bug: 1030266
Change-Id: I4ded091c29d29dd48bbd2b18a0d381395cb3f5f7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1948927
Commit-Queue: Michael van Ouwerkerk <[email protected]>
Reviewed-by: Richard Knoll <[email protected]>
Cr-Commit-Position: refs/heads/master@{#721034}
diff --git a/chrome/browser/sharing/features.h b/chrome/browser/sharing/features.h
index 2541e433..97b82ecc 100644
--- a/chrome/browser/sharing/features.h
+++ b/chrome/browser/sharing/features.h
@@ -6,6 +6,7 @@
 #define CHROME_BROWSER_SHARING_FEATURES_H_
 
 #include "base/feature_list.h"
+#include "base/metrics/field_trial_params.h"
 
 // Feature flag to allow sharing infrastructure to register devices in
 // DeviceInfo.
@@ -17,4 +18,10 @@
 // Feature flag to enable deriving VAPID key from Sync.
 extern const base::Feature kSharingDeriveVapidKey;
 
+// Feature flag for configuring device expiration.
+extern const base::Feature kSharingDeviceExpiration;
+
+// The number of hours after which a device is considered expired.
+extern const base::FeatureParam<int> kSharingDeviceExpirationHours;
+
 #endif  // CHROME_BROWSER_SHARING_FEATURES_H_