To accommodate some downstream WebRTC users we need to loosen
the coupling between our code and the //third_party/protobuf.

This includes using typedefs to define strings instead of
assuming std::string.

After this refactoring it will be possible to link with other
protobuf implementations than the current one.

We moved the PRESUBMIT check to another CL [1]. The goal of this
presubmit is to avoid the direct usage of google::protobuf outside
of the webrtc/base/protobuf_utils.h header file.

[1] - https://codereview.webrtc.org/2753823003/

BUG=webrtc:7340
NOTRY=True

Review-Url: https://codereview.webrtc.org/2747863003
Cr-Commit-Position: refs/heads/master@{#17466}
diff --git a/webrtc/modules/audio_coding/neteq/neteq_unittest.cc b/webrtc/modules/audio_coding/neteq/neteq_unittest.cc
index c52f2d6..47073fb 100644
--- a/webrtc/modules/audio_coding/neteq/neteq_unittest.cc
+++ b/webrtc/modules/audio_coding/neteq/neteq_unittest.cc
@@ -25,6 +25,7 @@
 #include "webrtc/base/ignore_wundef.h"
 #include "webrtc/base/sha1digest.h"
 #include "webrtc/base/stringencode.h"
+#include "webrtc/base/protobuf_utils.h"
 #include "webrtc/modules/audio_coding/codecs/pcm16b/pcm16b.h"
 #include "webrtc/modules/audio_coding/neteq/tools/audio_loop.h"
 #include "webrtc/modules/audio_coding/neteq/tools/rtp_file_source.h"
@@ -194,7 +195,7 @@
   neteq_unittest::NetEqNetworkStatistics stats;
   Convert(stats_raw, &stats);
 
-  std::string stats_string;
+  ProtoString stats_string;
   ASSERT_TRUE(stats.SerializeToString(&stats_string));
   AddMessage(output_fp_, digest_.get(), stats_string);
 #else
@@ -207,7 +208,7 @@
   neteq_unittest::RtcpStatistics stats;
   Convert(stats_raw, &stats);
 
-  std::string stats_string;
+  ProtoString stats_string;
   ASSERT_TRUE(stats.SerializeToString(&stats_string));
   AddMessage(output_fp_, digest_.get(), stats_string);
 #else