Add QuicLRUCache.

net/quic/core/crypto/quic_compressed_certs_cache.cc

Index: net/quic/core/crypto/quic_compressed_certs_cache.cc
diff --git a/net/quic/core/crypto/quic_compressed_certs_cache.cc b/net/quic/core/crypto/quic_compressed_certs_cache.cc
index 7bcddc4c53ae2b717b683f3121eb45e84a6a9122..c9ba5301beb472a5815df6cff25be11afeb21f7d 100644
--- a/net/quic/core/crypto/quic_compressed_certs_cache.cc
+++ b/net/quic/core/crypto/quic_compressed_certs_cache.cc
@@ -76,13 +76,10 @@ const string* QuicCompressedCertsCache::GetCompressedCert(
 
   uint64_t key = ComputeUncompressedCertsHash(uncompressed_certs);
 
-  auto cached_it = certs_cache_.Get(key);
-
-  if (cached_it != certs_cache_.end()) {
-    const CachedCerts& cached_value = cached_it->second;
-    if (cached_value.MatchesUncompressedCerts(uncompressed_certs)) {
-      return cached_value.compressed_cert();
-    }
+  CachedCerts* cached_value = certs_cache_.Lookup(key);
+  if (cached_value != nullptr &&
+      cached_value->MatchesUncompressedCerts(uncompressed_certs)) {
+    return cached_value->compressed_cert();
   }
   return nullptr;
 }
@@ -98,15 +95,17 @@ void QuicCompressedCertsCache::Insert(
   uint64_t key = ComputeUncompressedCertsHash(uncompressed_certs);
 
   // Insert one unit to the cache.
-  certs_cache_.Put(key, CachedCerts(uncompressed_certs, compressed_cert));
+  std::unique_ptr<CachedCerts> cached_certs(
+      new CachedCerts(uncompressed_certs, compressed_cert));
+  certs_cache_.Insert(key, std::move(cached_certs));
 }
 
 size_t QuicCompressedCertsCache::MaxSize() {
-  return certs_cache_.max_size();
+  return certs_cache_.MaxSize();
 }
 
 size_t QuicCompressedCertsCache::Size() {
-  return certs_cache_.size();
+  return certs_cache_.Size();
 }
 
 uint64_t QuicCompressedCertsCache::ComputeUncompressedCertsHash(