Make QuicCryptoClientConfig only cache server configs for 1 week.

net/quic/core/quic_constants.h

Index: net/quic/core/quic_constants.h
diff --git a/net/quic/core/quic_constants.h b/net/quic/core/quic_constants.h
index 3350643876013b69351bb43f0191267e6cac622e..73f8d39c09bd13c888e5da8a2931443845d09b40 100644
--- a/net/quic/core/quic_constants.h
+++ b/net/quic/core/quic_constants.h
@@ -19,6 +19,7 @@ namespace net {
 // Simple time constants.
 const uint64_t kNumSecondsPerMinute = 60;
 const uint64_t kNumSecondsPerHour = kNumSecondsPerMinute * 60;
+const uint64_t kNumSecondsPerWeek = kNumSecondsPerHour * 24 * 7;
 const uint64_t kNumMicrosPerMilli = 1000;
 const uint64_t kNumMicrosPerSecond = 1000 * 1000;