Use saturated_cast<> instead of checked_cast<> for converting

net/disk_cache/simple/simple_index_unittest.cc

Index: net/disk_cache/simple/simple_index_unittest.cc
diff --git a/net/disk_cache/simple/simple_index_unittest.cc b/net/disk_cache/simple/simple_index_unittest.cc
index d763d7f55e1ff0858c3863922fb346408cb11ec9..1b0aee75235b6ca7a94db2955eb3e45d585c783c 100644
--- a/net/disk_cache/simple/simple_index_unittest.cc
+++ b/net/disk_cache/simple/simple_index_unittest.cc
@@ -34,8 +34,7 @@ const uint64_t kTestEntrySize = 789;
 
 }  // namespace
 
-
-class EntryMetadataTest  : public testing::Test {
+class EntryMetadataTest : public testing::Test {
  public:
   EntryMetadata NewEntryMetadataWithValues() {
     return EntryMetadata(kTestLastUsedTime, kTestEntrySize);
@@ -186,6 +185,25 @@ TEST_F(EntryMetadataTest, Basics) {
             entry_metadata.GetLastUsedTime());
 }
 
+// Tests that setting an unusually small/large last used time results in
+// truncation (rather than crashing).
+TEST_F(EntryMetadataTest, SaturatedLastUsedTime) {
+  EntryMetadata entry_metadata;
+
+  // Set a time that is too large to be represented internally as 32-bit unix
+  // timestamp. Will saturate to a large timestamp (in year 2106).
+  entry_metadata.SetLastUsedTime(base::Time::Max());
+  EXPECT_EQ(INT64_C(15939440895000000),
+            entry_metadata.GetLastUsedTime().ToInternalValue());
+
+  // Set a time that is too small to be represented by a unix timestamp (before
+  // 1970).
+  entry_metadata.SetLastUsedTime(
+      base::Time::FromInternalValue(7u));  // This is a date in 1601.
+  EXPECT_EQ(base::Time::UnixEpoch() + base::TimeDelta::FromSeconds(1),
+            entry_metadata.GetLastUsedTime());
+}
+
 TEST_F(EntryMetadataTest, Serialize) {
   EntryMetadata entry_metadata = NewEntryMetadataWithValues();