[Sync] Subclass BrowserThreadModelWorker with descriptive names

This is so that we can distinguish threads from stack traces alone.

BUG=97271
TEST=

Review URL: http://codereview.chromium.org/8002032

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@102773 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 27 insertions, 4 deletions

diff --git a/chrome/browser/sync/glue/browser_thread_model_worker.cc b/chrome/browser/sync/glue/browser_thread_model_worker.cc
index 49bdfb8..7e76630 100644
--- a/chrome/browser/sync/glue/browser_thread_model_worker.cc
+++ b/chrome/browser/sync/glue/browser_thread_model_worker.cc
@@ -49,4 +49,14 @@ ModelSafeGroup BrowserThreadModelWorker::GetModelSafeGroup() {
   return group_;
 }
 
+DatabaseModelWorker::DatabaseModelWorker()
+    : BrowserThreadModelWorker(BrowserThread::DB, GROUP_DB) {}
+
+DatabaseModelWorker::~DatabaseModelWorker() {}
+
+FileModelWorker::FileModelWorker()
+    : BrowserThreadModelWorker(BrowserThread::FILE, GROUP_FILE) {}
+
+FileModelWorker::~FileModelWorker() {}
+
 }  // namespace browser_sync
diff --git a/chrome/browser/sync/glue/browser_thread_model_worker.h b/chrome/browser/sync/glue/browser_thread_model_worker.h
index 51670a1..9720cdb 100644
--- a/chrome/browser/sync/glue/browser_thread_model_worker.h
+++ b/chrome/browser/sync/glue/browser_thread_model_worker.h
@@ -39,6 +39,21 @@ class BrowserThreadModelWorker : public browser_sync::ModelSafeWorker {
   DISALLOW_COPY_AND_ASSIGN(BrowserThreadModelWorker);
 };
 
+// Subclass BrowserThreadModelWorker so that we can distinguish them
+// from stack traces alone.
+
+class DatabaseModelWorker : public BrowserThreadModelWorker {
+ public:
+  DatabaseModelWorker();
+  virtual ~DatabaseModelWorker();
+};
+
+class FileModelWorker : public BrowserThreadModelWorker {
+ public:
+  FileModelWorker();
+  virtual ~FileModelWorker();
+};
+
 }  // namespace browser_sync
 
 #endif  // CHROME_BROWSER_SYNC_GLUE_BROWSER_THREAD_MODEL_WORKER_H_
diff --git a/chrome/browser/sync/glue/sync_backend_registrar.cc b/chrome/browser/sync/glue/sync_backend_registrar.cc
index 7f1ea45..6408104 100644
--- a/chrome/browser/sync/glue/sync_backend_registrar.cc
+++ b/chrome/browser/sync/glue/sync_backend_registrar.cc
@@ -60,10 +60,8 @@ SyncBackendRegistrar::SyncBackendRegistrar(
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   CHECK(profile_);
   DCHECK(sync_loop_);
-  workers_[GROUP_DB] =
-      new BrowserThreadModelWorker(BrowserThread::DB, GROUP_DB);
-  workers_[GROUP_FILE] =
-      new BrowserThreadModelWorker(BrowserThread::FILE, GROUP_FILE);
+  workers_[GROUP_DB] = new DatabaseModelWorker();
+  workers_[GROUP_FILE] = new FileModelWorker();
   workers_[GROUP_UI] = ui_worker_;
   workers_[GROUP_PASSIVE] = new ModelSafeWorker();