Revert of Loosening the coupling between WebRTC and //third_party/protobuf

webrtc/modules/audio_processing/test/protobuf_utils.cc

Index: webrtc/modules/audio_processing/test/protobuf_utils.cc
diff --git a/webrtc/modules/audio_processing/test/protobuf_utils.cc b/webrtc/modules/audio_processing/test/protobuf_utils.cc
index cb8adf92ff2e984c84c9c9b361b1defa7a50e829..c18a13e6edfe306688491efe17f834169484e9d3 100644
--- a/webrtc/modules/audio_processing/test/protobuf_utils.cc
+++ b/webrtc/modules/audio_processing/test/protobuf_utils.cc
@@ -30,7 +30,7 @@
 }
 
 // Returns true on success, false on error or end-of-file.
-bool ReadMessageFromFile(FILE* file, MessageLite* msg) {
+bool ReadMessageFromFile(FILE* file, ::google::protobuf::MessageLite* msg) {
   std::unique_ptr<uint8_t[]> bytes;
   size_t size = ReadMessageBytesFromFile(file, &bytes);
   if (!size)