Add new ANA stats to GetStats() to count the number of actions taken by each controller.

webrtc/common_types.h

Index: webrtc/common_types.h
diff --git a/webrtc/common_types.h b/webrtc/common_types.h
index ac5c2e2e7b5aeaf7673a2b790c5cb0fd9ff69268..9e88d1f0e7b29e086af1f978278b473c4365a000 100644
--- a/webrtc/common_types.h
+++ b/webrtc/common_types.h
@@ -433,6 +433,18 @@ struct AudioDecodingCallStats {
   int decoded_muted_output;  // Number of calls returning a muted state output.
 };
 
+// Statistics related to Audio Network Adaptation.
+struct ANAStats {
+  ANAStats();
+  ANAStats(const ANAStats&);
+  ~ANAStats();

[hbos, 2017/09/04 08:49:54]

Is this a style-guide thing or can these be omitted, since they're all =
default?

[ossu, 2017/09/04 11:23:02]

Due to the Optional<> members, clang(-tidy) decides that the struct is complex
enough that the constructors / destructors mustn't be inline.

+  rtc::Optional<int> bitrate_action_counter;
+  rtc::Optional<int> channel_action_counter;
+  rtc::Optional<int> dtx_action_counter;
+  rtc::Optional<int> fec_action_counter;
+  rtc::Optional<int> frame_length_action_counter;

[hbos, 2017/09/04 08:49:54]

Please add comments explaining these.

Also, prefer one of the types int32_t, uint32_t, int64_t, uint64_t for integers
when working with stats. int or int32_t shouldn't matter in this case but I
prefer all new stats code to be explicit about the type like that because the
new api and spec is and stats are exported to other formats (javascript, jni,
etc).

[ivoc, 2017/09/04 15:48:00]

Added comments and changed these to uint32_t.

+};
+
 // ==================================================================
 // Video specific types
 // ==================================================================