Extract testing utility TestGetContentCallback.

chrome/browser/google_apis/fake_drive_service_unittest.cc

Index: chrome/browser/google_apis/fake_drive_service_unittest.cc
diff --git a/chrome/browser/google_apis/fake_drive_service_unittest.cc b/chrome/browser/google_apis/fake_drive_service_unittest.cc
index 7a5b43d7e44a3493c25ec9ee9dba7771b249084b..4699e0045ad1fad053f867c059e4f58775cc1794 100644
--- a/chrome/browser/google_apis/fake_drive_service_unittest.cc
+++ b/chrome/browser/google_apis/fake_drive_service_unittest.cc
@@ -91,14 +91,6 @@ class FakeDriveServiceTest : public testing::Test {
   FakeDriveService fake_service_;
 };
 
-void AppendGetContentCallbackResult(
-    std::vector<std::string>* values,
-    GDataErrorCode error,
-    scoped_ptr<std::string> content) {
-  DCHECK_EQ(error, HTTP_SUCCESS);  // Should always HTTP_SUCCESS.
-  values->push_back(*content);
-}
-
 void AppendProgressCallbackResult(std::vector<int64>* values, int64 progress) {
   values->push_back(progress);
 }
@@ -864,13 +856,13 @@ TEST_F(FakeDriveServiceTest, DownloadFile_ExistingFile) {
       temp_dir.path().AppendASCII("whatever.txt");
   GDataErrorCode error = GDATA_OTHER_ERROR;
   base::FilePath output_file_path;
-  std::vector<std::string> content_buffer;
+  test_util::TestGetContentCallback get_content_callback;
   fake_service_.DownloadFile(
       base::FilePath::FromUTF8Unsafe("/drive/whatever.txt"),  // virtual path
       kOutputFilePath,
       kContentUrl,
       test_util::CreateCopyResultCallback(&error, &output_file_path),
-      base::Bind(&AppendGetContentCallbackResult, &content_buffer),
+      get_content_callback.callback(),
       base::Bind(&test_util::AppendProgressCallbackResult,
                  &download_progress_values));
   message_loop_.RunUntilIdle();
@@ -885,12 +877,7 @@ TEST_F(FakeDriveServiceTest, DownloadFile_ExistingFile) {
   EXPECT_TRUE(base::STLIsSorted(download_progress_values));
   EXPECT_GE(download_progress_values.front().first, 0);
   EXPECT_LE(download_progress_values.back().first, 10);
-
-  std::string concatenated_content;
-  for (size_t i = 0; i < content_buffer.size(); ++i) {
-    concatenated_content += content_buffer[i];
-  }
-  EXPECT_EQ(content, concatenated_content);
+  EXPECT_EQ(content, get_content_callback.GetConcatenatedData());
 }
 
 TEST_F(FakeDriveServiceTest, DownloadFile_NonexistingFile) {