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_processing/audio_processing_unittest.cc b/webrtc/modules/audio_processing/audio_processing_unittest.cc
index b52acce..814eea9 100644
--- a/webrtc/modules/audio_processing/audio_processing_unittest.cc
+++ b/webrtc/modules/audio_processing/audio_processing_unittest.cc
@@ -20,6 +20,7 @@
 #include "webrtc/base/checks.h"
 #include "webrtc/base/gtest_prod_util.h"
 #include "webrtc/base/ignore_wundef.h"
+#include "webrtc/base/protobuf_utils.h"
 #include "webrtc/common_audio/include/audio_util.h"
 #include "webrtc/common_audio/resampler/include/push_resampler.h"
 #include "webrtc/common_audio/resampler/push_sinc_resampler.h"
@@ -58,7 +59,7 @@
 // file. This is the typical case. When the file should be updated, it can
 // be set to true with the command-line switch --write_ref_data.
 bool write_ref_data = false;
-const google::protobuf::int32 kChannels[] = {1, 2};
+const int32_t kChannels[] = {1, 2};
 const int kSampleRates[] = {8000, 16000, 32000, 48000};
 
 #if defined(WEBRTC_AUDIOPROC_FIXED_PROFILE)
@@ -230,7 +231,7 @@
 #endif
 
 void OpenFileAndWriteMessage(const std::string filename,
-                             const ::google::protobuf::MessageLite& msg) {
+                             const MessageLite& msg) {
   FILE* file = fopen(filename.c_str(), "wb");
   ASSERT_TRUE(file != NULL);
 
@@ -299,8 +300,7 @@
     remove(kv.second.c_str());
 }
 
-void OpenFileAndReadMessage(std::string filename,
-                            ::google::protobuf::MessageLite* msg) {
+void OpenFileAndReadMessage(std::string filename, MessageLite* msg) {
   FILE* file = fopen(filename.c_str(), "rb");
   ASSERT_TRUE(file != NULL);
   ReadMessageFromFile(file, msg);