[Sync] Make syncer commands avoid posting tasks on threads with no work to do

chrome/browser/sync/test/engine/syncer_command_test.h

Index: chrome/browser/sync/test/engine/syncer_command_test.h
diff --git a/chrome/browser/sync/test/engine/syncer_command_test.h b/chrome/browser/sync/test/engine/syncer_command_test.h
index c6fccbb21e9e5c2d2633a4ada91dbfd5e55c0d72..5dabf7fecfa18fdb409e63d8a77d9b3e10c35dce 100644
--- a/chrome/browser/sync/test/engine/syncer_command_test.h
+++ b/chrome/browser/sync/test/engine/syncer_command_test.h
@@ -12,6 +12,7 @@
 
 #include "base/compiler_specific.h"
 #include "base/message_loop.h"
+#include "chrome/browser/sync/engine/model_changing_syncer_command.h"
 #include "chrome/browser/sync/engine/model_safe_worker.h"
 #include "chrome/browser/sync/sessions/debug_info_getter.h"
 #include "chrome/browser/sync/sessions/sync_session.h"
@@ -157,6 +158,29 @@ class SyncerCommandTestWithParam : public testing::TestWithParam<T>,
     return &mock_debug_info_getter_;
   }
 
+  void ExpectNoGroupsToChange(
+      const ModelChangingSyncerCommand& command) {
+    EXPECT_TRUE(command.GetGroupsToChangeForTest(*session()).empty());
+  }
+
+  void ExpectGroupToChange(
+      const ModelChangingSyncerCommand& command, ModelSafeGroup group) {
+    std::set<ModelSafeGroup> expected_groups_to_change;
+    expected_groups_to_change.insert(group);
+    EXPECT_EQ(expected_groups_to_change,
+              command.GetGroupsToChangeForTest(*session()));
+  }
+
+  void ExpectGroupsToChange(
+      const ModelChangingSyncerCommand& command,
+      ModelSafeGroup group1, ModelSafeGroup group2) {
+    std::set<ModelSafeGroup> expected_groups_to_change;
+    expected_groups_to_change.insert(group1);
+    expected_groups_to_change.insert(group2);
+    EXPECT_EQ(expected_groups_to_change,
+              command.GetGroupsToChangeForTest(*session()));
+  }
+
  private:
   MessageLoop message_loop_;
   scoped_ptr<TestDirectorySetterUpper> syncdb_;