Add a keypress field to the audioproc debug proto.

Log the value in AudioProcessing, and unpack it to a new file in the
unpacking tool.

TESTED=
- The new tool can unpack old dumps.
- The old tool can unpack new dumps (without keypress.bool).
- Unpacking a new dump from voe_cmd_test produces a keypress.bool that
appears correct when examined.

R=aluebs@webrtc.org, bjornv@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/8509005

git-svn-id: http://webrtc.googlecode.com/svn/trunk@5535 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/webrtc/modules/audio_processing/debug.proto b/webrtc/modules/audio_processing/debug.proto
index 4b3a163..fb8e79a 100644
--- a/webrtc/modules/audio_processing/debug.proto
+++ b/webrtc/modules/audio_processing/debug.proto
@@ -20,6 +20,7 @@
   optional int32 delay = 3;
   optional sint32 drift = 4;
   optional int32 level = 5;
+  optional bool keypress = 6;
 }
 
 message Event {