Fix uninitialized access in QuicInMemoryCache::GetKey

net/tools/quic/quic_in_memory_cache.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/tools/quic/quic_in_memory_cache.h"
 
 #include "base/file_util.h"
 #include "base/files/file_enumerator.h"
 #include "base/stl_util.h"
 #include "base/strings/string_number_conversions.h"
@@ skipping 196 matching lines @@
     file = file_list.Next();
   }
 }
 
 QuicInMemoryCache::~QuicInMemoryCache() {
   STLDeleteValues(&responses_);
 }
 
 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");
   } else if (StringPieceUtils::StartsWithIgnoreCase(uri, "https://")) {
     uri.remove_prefix(8);
   } else if (StringPieceUtils::StartsWithIgnoreCase(uri, "http://")) {
     uri.remove_prefix(7);
   }
   return host.as_string() + uri.as_string();
 }
 
 }  // namespace tools
 }  // namespace net