Don't link with audio codecs that we don't use

webrtc/modules/audio_coding/main/acm2/acm_receiver_unittest.cc

Index: webrtc/modules/audio_coding/main/acm2/acm_receiver_unittest.cc
diff --git a/webrtc/modules/audio_coding/main/acm2/acm_receiver_unittest.cc b/webrtc/modules/audio_coding/main/acm2/acm_receiver_unittest.cc
index 0711a133d4a9f5b49e5f43529803209e477779ca..ff9c91115a500e5298f26816a72d4473a396afb1 100644
--- a/webrtc/modules/audio_coding/main/acm2/acm_receiver_unittest.cc
+++ b/webrtc/modules/audio_coding/main/acm2/acm_receiver_unittest.cc
@@ -293,7 +293,13 @@ TEST_F(AcmReceiverTest, DISABLED_ON_ANDROID(PostdecodingVad)) {
   EXPECT_EQ(AudioFrame::kVadUnknown, frame.vad_activity_);
 }
 
-TEST_F(AcmReceiverTest, DISABLED_ON_ANDROID(LastAudioCodec)) {
+#ifdef WEBRTC_CODEC_ISAC
+#define IF_ISAC_FLOAT(x) x
+#else
+#define IF_ISAC_FLOAT(x) DISABLED_##x
+#endif
+
+TEST_F(AcmReceiverTest, DISABLED_ON_ANDROID(IF_ISAC_FLOAT(LastAudioCodec))) {
   const int kCodecId[] = {
       ACMCodecDB::kISAC, ACMCodecDB::kPCMA, ACMCodecDB::kISACSWB,
       ACMCodecDB::kPCM16Bswb32kHz,