[Sync] Implement encryption-aware conflict resolution.

chrome/browser/sync/syncable/directory_backing_store.cc

Index: chrome/browser/sync/syncable/directory_backing_store.cc
diff --git a/chrome/browser/sync/syncable/directory_backing_store.cc b/chrome/browser/sync/syncable/directory_backing_store.cc
index 1f5294dfbc2097dcf78687beecd4ddfedefa9cd9..ac36232bfbe4ab82e121fc6d0fff99188fc26892 100644
--- a/chrome/browser/sync/syncable/directory_backing_store.cc
+++ b/chrome/browser/sync/syncable/directory_backing_store.cc
@@ -42,7 +42,7 @@ static const string::size_type kUpdateStatementBufferSize = 2048;
 
 // Increment this version whenever updating DB tables.
 extern const int32 kCurrentDBVersion;  // Global visibility for our unittest.
-const int32 kCurrentDBVersion = 77;
+const int32 kCurrentDBVersion = 78;
 
 namespace {
 
@@ -476,6 +476,12 @@ DirOpenResult DirectoryBackingStore::InitializeTables() {
       version_on_disk = 77;
   }
 
+  // Version 78 added the column base_server_specifics to the metas table.
+  if (version_on_disk == 77) {
+    if (MigrateVersion77To78())
+      version_on_disk = 78;
+  }
+
   // If one of the migrations requested it, drop columns that aren't current.
   // It's only safe to do this after migrating all the way to the current
   // version.
@@ -1118,6 +1124,17 @@ bool DirectoryBackingStore::MigrateVersion76To77() {
   return true;
 }
 
+bool DirectoryBackingStore::MigrateVersion77To78() {
+  // Version 78 added one column to table 'metas': base_server_specifics.
+  int result =
+      ExecQuery(load_dbhandle_,
+                "ALTER TABLE metas ADD COLUMN base_server_specifics BLOB");
+  if (result != SQLITE_DONE)
+    return false;
+  SetVersion(78);
+  return true;
+}
+
 int DirectoryBackingStore::CreateTables() {
   DVLOG(1) << "First run, creating tables";
   // Create two little tables share_version and share_info