Fixing WebRTC after moving from src/webrtc to src/

In https://webrtc-review.googlesource.com/c/src/+/1560 we moved WebRTC
from src/webrtc to src/ (in order to preserve an healthy git history).
This CL takes care of fixing header guards, #include paths, etc...

NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
TBR=tommi@webrtc.org


Bug: chromium:611808
Change-Id: Iea91618212bee0af16aa3f05071eab8f93706578
Reviewed-on: https://webrtc-review.googlesource.com/1561
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Reviewed-by: Henrik Kjellander <kjellander@webrtc.org>
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#19846}
diff --git a/api/datachannelinterface.h b/api/datachannelinterface.h
index 1395a2e..4ab7efb 100644
--- a/api/datachannelinterface.h
+++ b/api/datachannelinterface.h
@@ -11,15 +11,15 @@
 // This file contains interfaces for DataChannels
 // http://dev.w3.org/2011/webrtc/editor/webrtc.html#rtcdatachannel
 
-#ifndef WEBRTC_API_DATACHANNELINTERFACE_H_
-#define WEBRTC_API_DATACHANNELINTERFACE_H_
+#ifndef API_DATACHANNELINTERFACE_H_
+#define API_DATACHANNELINTERFACE_H_
 
 #include <string>
 
-#include "webrtc/rtc_base/basictypes.h"
-#include "webrtc/rtc_base/checks.h"
-#include "webrtc/rtc_base/copyonwritebuffer.h"
-#include "webrtc/rtc_base/refcount.h"
+#include "rtc_base/basictypes.h"
+#include "rtc_base/checks.h"
+#include "rtc_base/copyonwritebuffer.h"
+#include "rtc_base/refcount.h"
 
 namespace webrtc {
 
@@ -180,4 +180,4 @@
 
 }  // namespace webrtc
 
-#endif  // WEBRTC_API_DATACHANNELINTERFACE_H_
+#endif  // API_DATACHANNELINTERFACE_H_