Add unit tests for RedirectToFileResourceHandler.

content/browser/loader/test_resource_handler.cc

Index: content/browser/loader/test_resource_handler.cc
diff --git a/content/browser/loader/test_resource_handler.cc b/content/browser/loader/test_resource_handler.cc
index 6cd13a9aa53c076d9f9ac9e0684b9d2e5c9d4ac4..a6c8072530dd879fbc0eae6711fd6d388a3dad40 100644
--- a/content/browser/loader/test_resource_handler.cc
+++ b/content/browser/loader/test_resource_handler.cc
@@ -202,6 +202,10 @@ void TestResourceHandler::OnResponseCompleted(
 
 void TestResourceHandler::OnDataDownloaded(int bytes_downloaded) {
   EXPECT_TRUE(expect_on_data_downloaded_);
+  EXPECT_EQ(1, on_will_start_called_);
+  EXPECT_EQ(1, on_response_started_called_);
+  EXPECT_EQ(0, on_response_completed_called_);
+
   total_bytes_downloaded_ += bytes_downloaded;
 }