Enable cpplint and fix cpplint errors in webrtc/*audio

webrtc/common_audio/vad/vad_filterbank_unittest.cc

Index: webrtc/common_audio/vad/vad_filterbank_unittest.cc
diff --git a/webrtc/common_audio/vad/vad_filterbank_unittest.cc b/webrtc/common_audio/vad/vad_filterbank_unittest.cc
index 5b278013e8ed83e9ddcf3e7d97ae877451c02f60..d15fc1b4877316f524ccdcfc940a5882cf76d301 100644
--- a/webrtc/common_audio/vad/vad_filterbank_unittest.cc
+++ b/webrtc/common_audio/vad/vad_filterbank_unittest.cc
@@ -19,7 +19,8 @@ extern "C" {
 #include "webrtc/common_audio/vad/vad_filterbank.h"
 }
 
-namespace {
+namespace webrtc {
+namespace test {
 
 const int kNumValidFrameLengths = 3;
 
@@ -89,4 +90,5 @@ TEST_F(VadTest, vad_filterbank) {
 
   free(self);
 }
-}  // namespace
+}  // namespace test
+}  // namespace webrtc