LogDog: Support per-namespace expired archival.

common/proto/logdog/svcconfig/config.proto

Index: common/proto/logdog/svcconfig/config.proto
diff --git a/common/proto/logdog/svcconfig/config.proto b/common/proto/logdog/svcconfig/config.proto
index de5c19c4447892e800a79d5fc297d063a00a17c0..1391687352283229e471b9ec92305a265ec71ba5 100644
--- a/common/proto/logdog/svcconfig/config.proto
+++ b/common/proto/logdog/svcconfig/config.proto
@@ -39,10 +39,13 @@ message Coordinator {
   // A list of origin URLs that are allowed to perform CORS RPC calls.
   repeated string rpc_allow_origins = 20;
 
+  // The name of the task queue for project-specific archival scans.
+  string archive_scan_project_queue_name = 30;
+
   // The full path of the archival Pub/Sub topic.
   //
   // The Coordinator must have permission to publish to this topic.
-  string archive_topic = 30;
+  string archive_topic = 31;
 
   // The amount of time after an archive request has been dispatched before it
   // should be executed.
@@ -54,7 +57,7 @@ message Coordinator {
   //
   // This parameter is an optimization to stop the archivist from wasting its
   // time until the log stream has a reasonable expectation of being available.
-  google.protobuf.Duration archive_settle_delay = 31;
+  google.protobuf.Duration archive_settle_delay = 32;
 
   // The amount of time before a log stream is candidate for archival regardless
   // of whether or not it's been terminated or complete.
@@ -65,7 +68,7 @@ message Coordinator {
   // This should be fairly large (days) to avoid prematurely archiving
   // long-running streams, but should be considerably smaller than the
   // intermediate storage data retention period.
-  google.protobuf.Duration archive_delay_max = 32;
+  google.protobuf.Duration archive_delay_max = 33;
 }
 
 // Collector is the set of configuration parameters for Collector instances.