Create //webrtc/api:libjingle_peerconnection_api + refactorings.

webrtc/pc/dtmfsender.h

Index: webrtc/pc/dtmfsender.h
diff --git a/webrtc/api/dtmfsender.h b/webrtc/pc/dtmfsender.h
similarity index 97%
rename from webrtc/api/dtmfsender.h
rename to webrtc/pc/dtmfsender.h
index d4e8f06d9e1e78ebe6bd33726ed7d59121bfca29..1163adfaed3cbbff92e40d569873f1b237c359d6 100644
--- a/webrtc/api/dtmfsender.h
+++ b/webrtc/pc/dtmfsender.h
@@ -8,8 +8,8 @@
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
-#ifndef WEBRTC_API_DTMFSENDER_H_
-#define WEBRTC_API_DTMFSENDER_H_
+#ifndef WEBRTC_PC_DTMFSENDER_H_
+#define WEBRTC_PC_DTMFSENDER_H_
 
 #include <string>
 
@@ -121,4 +121,4 @@ bool GetDtmfCode(char tone, int* code);
 
 }  // namespace webrtc
 
-#endif  // WEBRTC_API_DTMFSENDER_H_
+#endif  // WEBRTC_PC_DTMFSENDER_H_