Register header extensions in RtpRtcpObserver to avoid log spam.

webrtc/test/constants.h

Index: webrtc/test/constants.h
diff --git a/webrtc/modules/audio_device/android/ensure_initialized.h b/webrtc/test/constants.h
similarity index 72%
copy from webrtc/modules/audio_device/android/ensure_initialized.h
copy to webrtc/test/constants.h
index c1997b4acdf1484a41bffef16f66809e49fa6e90..14b2ba65bc202946cb1f58c5d12e10c272668f35 100644
--- a/webrtc/modules/audio_device/android/ensure_initialized.h
+++ b/webrtc/test/constants.h
@@ -9,9 +9,10 @@
  */
 
 namespace webrtc {
-namespace audiodevicemodule {
+namespace test {
 
-void EnsureInitialized();
-
-}  // namespace audiodevicemodule
+extern const int kTOffsetExtensionId;
+extern const int kAbsSendTimeExtensionId;
+extern const int kTransportSequenceNumberExtensionId;
+}  // namespace test
 }  // namespace webrtc