webrtc-apm: Fix dependency to debug.pb.h

Per common-mk document, add missing 'depends' lines for targets that
depend on debug.pb.h

BUG=chromium:923764
TEST=emerge-atlas webrtc-apm

Change-Id: I8334453e3c366157f05ceba1d13987c47b90cc16
Reviewed-on: https://chromium-review.googlesource.com/1534212
Commit-Ready: Hsinyu Chao <hychao@chromium.org>
Tested-by: Hsinyu Chao <hychao@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
diff --git a/modules/audio_processing/module.mk b/modules/audio_processing/module.mk
index d03942e..ee33c73 100644
--- a/modules/audio_processing/module.mk
+++ b/modules/audio_processing/module.mk
@@ -234,6 +234,11 @@
 clean: CLEAN($(PROTO_DIR)/debug.pb.h $(PROTO_DIR)/debug.pb.cc)
 $(eval $(call add_object_rules,$(PROTO_DIR)/debug.pb.o,CXX,cc,CXXFLAGS))
 
+modules/audio_processing/aec_dump/aec_dump_impl.o.depends \
+modules/audio_processing/aec_dump/capture_stream_info.o.depends \
+modules/audio_processing/aec_dump/write_to_file_task.o.depends: \
+	$(PROTO_DIR)/debug.pb.h
+
 audioproc_debug_proto_CXX_OBJECTS = \
 	$(PROTO_DIR)/debug.pb.o