Make IndexedDB layout browser tests save incorrect results to a file

content/test/layout_browsertest.cc

Index: content/test/layout_browsertest.cc
diff --git a/content/test/layout_browsertest.cc b/content/test/layout_browsertest.cc
index b0fac406abd02ff24baf3e7d8b555c8297f92730..3e9458221b33dea7c25f1530bb0f17e292681ac3 100644
--- a/content/test/layout_browsertest.cc
+++ b/content/test/layout_browsertest.cc
@@ -4,6 +4,7 @@
 
 #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"
@@ -16,6 +17,7 @@
 #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"
@@ -215,7 +217,13 @@ void InProcessBrowserLayoutTest::RunLayoutTestInternal(
   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);

[jam, 2012/09/05 01:33:37]

nit: I believe "<<" has to be at the start of the previous line per the style
guide

[dgrogan, 2012/09/05 02:03:30]

Done.

I couldn't find this case in (or infer from) either style guide, but what you
suggest is definitely consistent with code in chromium and google3.

+  } else {
+    EXPECT_EQ(expected_text, actual_text);
+  }
 }
 
 void InProcessBrowserLayoutTest::AddResourceForLayoutTest(
@@ -256,3 +264,20 @@ void InProcessBrowserLayoutTest::WriteModifiedFile(
                                    &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());
+}