Prepare to compile ACM1 and ACM2.

ACM1 code is wrapped in namespace acm1. Inculde paths and define guards of ACM2 source codes are corrected. gypi file of ACM2 is changed so that ACM1 will later on depends on ACM2.

BUG=
R=andrew@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/2206004

git-svn-id: http://webrtc.googlecode.com/svn/trunk/webrtc@4743 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/modules/audio_coding/main/source/acm_generic_codec.h b/modules/audio_coding/main/source/acm_generic_codec.h
index 9ba8d08..3951a94 100644
--- a/modules/audio_coding/main/source/acm_generic_codec.h
+++ b/modules/audio_coding/main/source/acm_generic_codec.h
@@ -27,6 +27,9 @@
 
 // forward declaration
 struct CodecInst;
+
+namespace acm1 {
+
 class ACMNetEQ;
 
 class ACMGenericCodec {
@@ -1213,6 +1216,8 @@
   uint32_t unique_id_;
 };
 
-}  // namespace webrt
+}  // namespace acm1
+
+}  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_AUDIO_CODING_MAIN_SOURCE_ACM_GENERIC_CODEC_H_