Fix uninitialized access in QuicInMemoryCache::GetKey

net/tools/quic/quic_in_memory_cache.cc

Index: net/tools/quic/quic_in_memory_cache.cc
diff --git a/net/tools/quic/quic_in_memory_cache.cc b/net/tools/quic/quic_in_memory_cache.cc
index c7c7cd04ebfd941cb54fd267a5071808c01b94cc..3b7c0a435c867ac8f5166ee0889aeb872d5180a6 100644
--- a/net/tools/quic/quic_in_memory_cache.cc
+++ b/net/tools/quic/quic_in_memory_cache.cc
@@ -214,6 +214,9 @@ QuicInMemoryCache::~QuicInMemoryCache() {
 
 string QuicInMemoryCache::GetKey(const BalsaHeaders& request_headers) const {
   StringPiece uri = request_headers.request_uri();
+  if (uri.size() == 0) {
+    return "";
+  }
   StringPiece host;
   if (uri[0] == '/') {
     host = request_headers.GetHeader("host");