[Sync] Add timeout for sharing messages

This patch introduces timeout error code which will be used every time
when the bridge didn't get response on sent message.

Bug: 1056210
Change-Id: I026769097d7eba349e90e5f292123a9ed323e489
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2082923
Reviewed-by: Robert Kaplow <[email protected]>
Reviewed-by: Michael van Ouwerkerk <[email protected]>
Reviewed-by: vitaliii <[email protected]>
Reviewed-by: Marc Treib <[email protected]>
Commit-Queue: Rushan Suleymanov <[email protected]>
Cr-Commit-Position: refs/heads/master@{#747166}
diff --git a/chrome/browser/sharing/features.h b/chrome/browser/sharing/features.h
index e65fe6dc..1941161 100644
--- a/chrome/browser/sharing/features.h
+++ b/chrome/browser/sharing/features.h
@@ -50,6 +50,10 @@
 // The FCM TTL in seconds for sharing ack messages.
 extern const base::FeatureParam<int> kSharingAckMessageTTLSeconds;
 
+// Feature flag for configuring the timeout in the sharing message bridge.
+extern const base::Feature kSharingMessageBridgeTimeout;
+extern const base::FeatureParam<int> kSharingMessageBridgeTimeoutSeconds;
+
 // Feature flag for sending sharing message via Sync.
 extern const base::Feature kSharingSendViaSync;