[Sync] Properly purge context/progress markers for disabled types

We were not properly purging all the context or progress marker info,
and it looks like we were even marking the kernel as dirty to ensure it
got saved into the directory. This fixes that, and tests it properly.

BUG=362307

Review URL: https://codereview.chromium.org/234403003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@263193 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 14 insertions, 7 deletions

diff --git a/sync/syncable/directory.cc b/sync/syncable/directory.cc
index 11bc956..e92f456 100644
--- a/sync/syncable/directory.cc
+++ b/sync/syncable/directory.cc
@@ -39,19 +39,22 @@ Directory::PersistedKernelInfo::PersistedKernelInfo()
   ModelTypeSet protocol_types = ProtocolTypes();
   for (ModelTypeSet::Iterator iter = protocol_types.First(); iter.Good();
        iter.Inc()) {
-    reset_download_progress(iter.Get());
+    ResetDownloadProgress(iter.Get());
     transaction_version[iter.Get()] = 0;
   }
 }
 
 Directory::PersistedKernelInfo::~PersistedKernelInfo() {}
 
-void Directory::PersistedKernelInfo::reset_download_progress(
+void Directory::PersistedKernelInfo::ResetDownloadProgress(
     ModelType model_type) {
+  // Clear everything except the data type id field.
+  download_progress[model_type].Clear();
   download_progress[model_type].set_data_type_id(
       GetSpecificsFieldNumberFromModelType(model_type));
-  // An empty-string token indicates no prior knowledge.
-  download_progress[model_type].set_token(std::string());
+
+  // Explicitly set an empty token field to denote no progress.
+  download_progress[model_type].set_token("");
 }
 
 Directory::SaveChangesSnapshot::SaveChangesSnapshot()
@@ -716,10 +719,14 @@ bool Directory::PurgeEntriesWithTypeIn(ModelTypeSet disabled_types,
            it.Good(); it.Inc()) {
         kernel_->persisted_info.transaction_version[it.Get()] = 0;
 
-        // Don't discard progress markers for unapplied types.
-        if (!types_to_unapply.Has(it.Get()))
-          kernel_->persisted_info.reset_download_progress(it.Get());
+        // Don't discard progress markers or context for unapplied types.
+        if (!types_to_unapply.Has(it.Get())) {
+          kernel_->persisted_info.ResetDownloadProgress(it.Get());
+          kernel_->persisted_info.datatype_context[it.Get()].Clear();
+        }
       }
+
+      kernel_->info_status = KERNEL_SHARE_INFO_DIRTY;
     }
   }
   return true;