Make IndexedDB layout browser tests save incorrect results to a file

content/test/layout_browsertest.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/test/layout_browsertest.h"
 
+#include "base/command_line.h"
 #include "base/file_path.h"
 #include "base/file_util.h"
 #include "base/path_service.h"
 #include "base/rand_util.h"
 #include "base/scoped_temp_dir.h"
 #include "base/stringprintf.h"
 #include "base/string_util.h"
 #include "base/utf_string_conversions.h"
 #include "content/browser/web_contents/web_contents_impl.h"
 #include "content/public/common/content_paths.h"
 #include "content/public/test/browser_test_utils.h"
 #include "content/shell/shell.h"
+#include "content/shell/shell_switches.h"
 #include "content/test/content_browser_test_utils.h"
 #include "content/test/layout_test_http_server.h"
 #include "net/base/net_util.h"
 
 #if defined(OS_WIN)
 static const char kPlatformName[] = "chromium-win";
 #elif defined(OS_MACOSX)
 static const char kPlatformName[] = "chromium-mac";
 #elif defined(OS_LINUX)
 static const char kPlatformName[] = "chromium-linux";
@@ skipping 179 matching lines @@
                             test_case_file_name,
                             &expected_text))
       ReadExpectedResult(our_original_layout_test_dir_,
                          test_case_file_name,
                          &expected_text);
   }
   ASSERT_TRUE(!expected_text.empty());
   ReplaceSubstringsAfterOffset(&expected_text, 0, "\r", "");
   TrimString(expected_text, "\n", &expected_text);
 
-  EXPECT_EQ(expected_text, actual_text);
+  CommandLine* command_line = CommandLine::ForCurrentProcess();
+  if (command_line->HasSwitch(switches::kOutputLayoutTestDifferences)) {
+    EXPECT_EQ(expected_text, actual_text) <<
+        SaveResults(expected_text, actual_text);
+  } else {
+    EXPECT_EQ(expected_text, actual_text);
+  }
 }
 
 void InProcessBrowserLayoutTest::AddResourceForLayoutTest(
     const FilePath& parent_dir,
     const FilePath& resource_name) {
   FilePath source;
   ASSERT_TRUE(PathService::Get(content::DIR_LAYOUT_TESTS, &source));
   source = source.Append(parent_dir);
   source = source.Append(resource_name);
 
@@ skipping 20 matching lines @@
   ASSERT_TRUE(file_util::ReadFileToString(path_to_single_test, &test_html));
 
   size_t insertion_position = FindInsertPosition(test_html);
   test_html.insert(insertion_position, preamble);
   *test_path = our_layout_test_temp_dir_.Append(test_case_dir_);
   *test_path = test_path->AppendASCII(test_case_file_name);
   ASSERT_TRUE(file_util::WriteFile(*test_path,
                                    &test_html.at(0),
                                    static_cast<int>(test_html.size())));
 }
+
+std::string InProcessBrowserLayoutTest::SaveResults(const std::string& expected,
+                                                    const std::string& actual) {
+  FilePath cwd;
+  EXPECT_TRUE(file_util::CreateNewTempDirectory(FILE_PATH_LITERAL(""), &cwd));
+  FilePath expected_filename = cwd.Append(FILE_PATH_LITERAL("expected.txt"));
+  FilePath actual_filename = cwd.Append(FILE_PATH_LITERAL("actual.txt"));
+  EXPECT_NE(-1, file_util::WriteFile(expected_filename,
+                                     expected.c_str(),
+                                     expected.size()));
+  EXPECT_NE(-1, file_util::WriteFile(actual_filename,
+                                     actual.c_str(),
+                                     actual.size()));
+  return StringPrintf("Wrote %"PRFilePath" %"PRFilePath,
+                      expected_filename.value().c_str(),
+                      actual_filename.value().c_str());
+}