Avoid discarding freshly created background tabs

content/browser/web_contents/web_contents_impl_unittest.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 "base/logging.h"
 #include "base/strings/utf_string_conversions.h"
 #include "content/browser/frame_host/interstitial_page_impl.h"
 #include "content/browser/frame_host/navigation_entry_impl.h"
 #include "content/browser/renderer_host/render_view_host_impl.h"
 #include "content/browser/site_instance_impl.h"
@@ skipping 2198 matching lines @@
   EXPECT_EQ(1, contents()->GetCapturerCount());
   EXPECT_EQ(capture_size, contents()->GetPreferredSize());
 
   // Decrement capturer count, and since the count has dropped to zero, the
   // original preferred size should be restored.
   contents()->DecrementCapturerCount();
   EXPECT_EQ(0, contents()->GetCapturerCount());
   EXPECT_EQ(original_preferred_size, contents()->GetPreferredSize());
 }
 
+// Tests that GetLastActiveTime starts with a real, non-zero time and updates
+// on activity.
+TEST_F(WebContentsImplTest, GetLastActiveTime) {
+  // The WebContents starts with a valid creation time.
+  EXPECT_FALSE(contents()->GetLastActiveTime().is_null());
+
+  // Reset the last active time to a known-bad value.
+  contents()->last_active_time_ = base::TimeTicks();
+  ASSERT_TRUE(contents()->GetLastActiveTime().is_null());
+
+  // Simulate activating the WebContents. The active time should update.
+  contents()->WasShown();
+  EXPECT_FALSE(contents()->GetLastActiveTime().is_null());
+}
+
 }  // namespace content