Fix bug where Navigation Timing reports negative load time when redirecting to

chrome/browser/net/load_timing_observer_uitest.cc

Index: chrome/browser/net/load_timing_observer_uitest.cc
diff --git a/chrome/browser/net/load_timing_observer_uitest.cc b/chrome/browser/net/load_timing_observer_uitest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..2127baff9a6d1560c4891d5b46c057197f212d93
--- /dev/null
+++ b/chrome/browser/net/load_timing_observer_uitest.cc
@@ -0,0 +1,40 @@
+// Copyright (c) 2011 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 "chrome/test/automation/tab_proxy.h"
+#include "chrome/test/ui/ui_test.h"
+#include "googleurl/src/gurl.h"
+#include "net/test/test_server.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+class LoadTimingObserverUITest : public UITest {
+ public:
+  LoadTimingObserverUITest()
+      : http_server_(net::TestServer::TYPE_HTTP, FilePath()) {
+    dom_automation_enabled_ = true;
+  }
+
+ protected:
+  net::TestServer http_server_;
+};
+
+TEST_F(LoadTimingObserverUITest, CacheHitAfterRedirect) {
+  ASSERT_TRUE(http_server_.Start());
+  GURL cached_page = http_server_.GetURL("cachetime");
+  std::string redirect = "server-redirect?" + cached_page.spec();
+  NavigateToURL(cached_page);
+  NavigateToURL(http_server_.GetURL(redirect));
+  scoped_refptr<TabProxy> tab_proxy = GetActiveTab();
+  int response_start = 0;
+  int response_end = 0;
+  ASSERT_TRUE(tab_proxy->ExecuteAndExtractInt(
+      L"", L"window.domAutomationController.send("
+      L"window.performance.timing.responseStart - "
+      L"window.performance.timing.navigationStart)", &response_start));
+  ASSERT_TRUE(tab_proxy->ExecuteAndExtractInt(
+      L"", L"window.domAutomationController.send("
+      L"window.performance.timing.responseEnd - "
+      L"window.performance.timing.navigationStart)", &response_end));
+  EXPECT_LE(response_start, response_end);
+}