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@4743 4adac7df-926f-26a2-2b94-8c16560cd09d

webrtc/modules/audio_coding/main/source/acm_generic_codec.cc

@@ -22,6 +22,8 @@
 
 namespace webrtc {
 
+namespace acm1 {
+
 // Enum for CNG
 enum {
   kMaxPLCParamsCNG = WEBRTC_CNG_MAX_LPC_ORDER,
@@ -1251,4 +1253,6 @@ int16_t ACMGenericCodec::REDPayloadISAC(const int32_t /* isac_rate */,
 
 bool ACMGenericCodec::IsTrueStereoCodec() { return false; }
 
+}  // namespace acm1
+
 }  // namespace webrtc