[SyncFS] Force activate folder tracker on folder creation conflict case

chrome/browser/sync_file_system/drive_backend/metadata_database.h

Index: chrome/browser/sync_file_system/drive_backend/metadata_database.h
diff --git a/chrome/browser/sync_file_system/drive_backend/metadata_database.h b/chrome/browser/sync_file_system/drive_backend/metadata_database.h
index 5cd673cc9f3a8222eb7c78815d91c8b3860e9359..34ed342074fcd93129da97fa33e9ba691641ff2f 100644
--- a/chrome/browser/sync_file_system/drive_backend/metadata_database.h
+++ b/chrome/browser/sync_file_system/drive_backend/metadata_database.h
@@ -125,7 +125,6 @@ class MetadataDatabase {
   enum ActivationStatus {
     ACTIVATION_PENDING,
     ACTIVATION_FAILED_ANOTHER_ACTIVE_TRACKER,
-    ACTIVATION_FAILED_SAME_PATH_TRACKER,
   };
 
   enum UpdateOption {
@@ -304,18 +303,23 @@ class MetadataDatabase {
                      const FileDetails& updated_details,
                      const SyncStatusCallback& callback);
 
-  // Returns ACTIVATION_PENDING if a tracker of the file can be safely activated
-  // without deactivating any other trackers.  In this case, tries to activate
-  // the tracker, and invokes |callback| upon completion.
-  // Returns ACTIVATION_FAILED_ANOTHER_ACTIVE_TRACKER if there's another active
-  // tracker that tracks |file_id|.
-  // Returns ACTIVATION_FAILED_SAME_PATH_TRACKER if there's another active
-  // tracker that has the same parent tracker and title to |file_id|.
-  // In these FAILED cases, |callback| is not invoked.
-  ActivationStatus TryNoSideEffectActivation(
-      int64 parent_tracker_id,
-      const std::string& file_id,
-      const SyncStatusCallback& callback);
+  // Activates a tracker identified by |parent_tracker_id| and |file_id| if the
+  // tracker can be activated without deactivating other trackers that have
+  // different path to the tracker to be activated.

[nhiroki, 2014/02/07 05:24:30]

nit: "... different path to the tracker to be activated." sounds a bit wordy to
me. "... other trackers that have same file_id but different path." would be
clearer...? wdyt?

[tzik, 2014/02/07 05:43:42]

Looks nice. Done.

+  // If |file_id| has another active tracker that is different to the tracker to
+  // be activated, the function returns ACTIVATION_FAILED_ANOTHER_ACTIVE_TRACKER

[nhiroki, 2014/02/07 05:24:30]

"another" and "different" seems the same meaning. How about "If |file_id| has
another active tracker, the function ..."?

[tzik, 2014/02/07 05:43:42]

Done.

+  // and does not invoke |callback|.
+  // If there is another active tracker that has the same path to the tracker to

[nhiroki, 2014/02/07 05:24:30]

"... that has the same path but different file_id, ..." ?

[tzik, 2014/02/07 05:43:42]

Done.

+  // be activated, inactivates it.

[nhiroki, 2014/02/07 05:24:30]

Can we use "deactivates" instead of "inactivates" (or vice verse) for
consistency?

[tzik, 2014/02/07 05:43:42]

Done.

+  // In success case, returns ACTIVATION_PENDING and invokes |callback| upon
+  // completion.
+  //
+  // The tracker to be activated must:
+  //  - have a tracked metadata in the database,
+  //  - have |synced_details| with valid |title|.
+  ActivationStatus TryActivateTracker(int64 parent_tracker_id,
+                                      const std::string& file_id,
+                                      const SyncStatusCallback& callback);
 
   // Changes the priority of the tracker to low.
   void LowerTrackerPriority(int64 tracker_id);