Add expiration policy, code to check it, and a test.

components/offline_pages/background/request_picker_unittest.cc

Index: components/offline_pages/background/request_picker_unittest.cc
diff --git a/components/offline_pages/background/request_picker_unittest.cc b/components/offline_pages/background/request_picker_unittest.cc
index e6c0092b4be3211b099fe653289225d74a91de91..633c1eb907d9f9b46de53302e24ac759ca2278ab 100644
--- a/components/offline_pages/background/request_picker_unittest.cc
+++ b/components/offline_pages/background/request_picker_unittest.cc
@@ -28,6 +28,7 @@ const GURL kUrl2("http://nytimes.com");
 const ClientId kClientId2("bookmark", "5678");
 const bool kUserRequested = true;
 const int kAttemptCount = 1;
+const int kTwoWeeksInSeconds = 60 * 60 * 24 * 7 * 2;
 
 // Constants for policy values - These settings represent the default values.
 const bool kPreferUntried = false;
@@ -248,4 +249,19 @@ TEST_F(RequestPickerTest, ChooseLaterRequest) {
   EXPECT_FALSE(request_queue_empty_called_);
 }
 
+TEST_F(RequestPickerTest, ChooseUnexpiredRequest) {
+  base::Time creation_time1 =
+      base::Time::Now() - base::TimeDelta::FromSeconds(kTwoWeeksInSeconds);
+  base::Time creation_time2 = base::Time::Now();
+  SavePageRequest request1(kRequestId1, kUrl1, kClientId1, creation_time1,
+                           kUserRequested);
+  SavePageRequest request2(kRequestId2, kUrl2, kClientId2, creation_time2,
+                           kUserRequested);
+
+  QueueRequestsAndChooseOne(request1, request2);
+
+  EXPECT_EQ(kRequestId2, last_picked_->request_id());
+  EXPECT_FALSE(request_queue_empty_called_);
+}
+
 }  // namespace offline_pages