[Sync] Fix namespaces for the browser_sync component.

components/browser_sync/profile_sync_service_mock.cc

Index: components/browser_sync/profile_sync_service_mock.cc
diff --git a/components/browser_sync/profile_sync_service_mock.cc b/components/browser_sync/profile_sync_service_mock.cc
index 1f0efde5856db77721f3cc03bf5fd14bbc23d0e6..d2dd85c1d218629736bb716d5f2f347b84569a24 100644
--- a/components/browser_sync/profile_sync_service_mock.cc
+++ b/components/browser_sync/profile_sync_service_mock.cc
@@ -6,6 +6,8 @@
 
 #include <utility>
 
+namespace browser_sync {
+
 ProfileSyncServiceMock::ProfileSyncServiceMock(InitParams init_params)
     : ProfileSyncService(std::move(init_params)) {
   ON_CALL(*this, IsSyncRequested()).WillByDefault(testing::Return(true));
@@ -15,3 +17,5 @@ ProfileSyncServiceMock::ProfileSyncServiceMock(InitParams* init_params)
     : ProfileSyncServiceMock(std::move(*init_params)) {}
 
 ProfileSyncServiceMock::~ProfileSyncServiceMock() {}
+
+}  // namespace browser_sync