sync: use progress markers instead of timestamps during GetUpdates

chrome/browser/sync/sessions/session_state.cc

 // Copyright (c) 2009 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/sync/sessions/session_state.h"
 
 #include <set>
 #include <vector>
 
 using std::set;
 using std::vector;
 
 namespace browser_sync {
 namespace sessions {
 
 SyncSessionSnapshot::SyncSessionSnapshot(
     const SyncerStatus& syncer_status,
     const ErrorCounters& errors,
     int64 num_server_changes_remaining,
-    int64 max_local_timestamp,
     bool is_share_usable,
     const syncable::ModelTypeBitSet& initial_sync_ended,
+    std::string download_progress_markers[syncable::MODEL_TYPE_COUNT],
     bool more_to_sync,
     bool is_silenced,
     int64 unsynced_count,
     int num_conflicting_updates,
     bool did_commit_items)
     : syncer_status(syncer_status),
       errors(errors),
       num_server_changes_remaining(num_server_changes_remaining),
-      max_local_timestamp(max_local_timestamp),
       is_share_usable(is_share_usable),
       initial_sync_ended(initial_sync_ended),
+      download_progress_markers(),
       has_more_to_sync(more_to_sync),
       is_silenced(is_silenced),
       unsynced_count(unsynced_count),
       num_conflicting_updates(num_conflicting_updates),
       did_commit_items(did_commit_items) {
+  for (int i = 0; i < syncable::MODEL_TYPE_COUNT; ++i) {
+    const_cast<std::string&>(this->download_progress_markers[i]).assign(
+        download_progress_markers[i]);
+  }
 }
 
 SyncSessionSnapshot::~SyncSessionSnapshot() {}
 
 ConflictProgress::ConflictProgress(bool* dirty_flag) : dirty_(dirty_flag) {}
 
 ConflictProgress::~ConflictProgress() {
   CleanupSets();
 }
 
@@ skipping 182 matching lines @@
 
 AllModelTypeState::~AllModelTypeState() {}
 
 PerModelSafeGroupState::PerModelSafeGroupState(bool* dirty_flag)
     : conflict_progress(dirty_flag) {
 }
 
 PerModelSafeGroupState::~PerModelSafeGroupState() {
 }
 
-PerModelTypeState::PerModelTypeState(bool* dirty_flag)
-    : current_download_timestamp(dirty_flag, 0) {
+PerModelTypeState::PerModelTypeState(bool* dirty_flag) {

[tim (not reviewing), 2011/01/11 19:14:23]

Is your reason for leaving this a) you're not sure if it is still needed, b) we
may want to add something here in the future so why remove all the plumbing, or
c) you don't want to make your patch larger?  I'm pretty sure it's not needed
now, and if we don't needed I'd rather see it go, which leaves (c), so I'd
suggest filing a bug and referencing it.  

Or is there a (d) I'm missing?

[ncarter (slow), 2011/01/13 00:06:13]

It was (b) ("might need in the future"), and you've convinced me that it can go.
 Done.

 }
 
 PerModelTypeState::~PerModelTypeState() {
 }
 
 }  // namespace sessions
 }  // namespace browser_sync