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/examples/peerconnection/client/main_wnd.h b/examples/peerconnection/client/main_wnd.h
index 18f56a7..f3ed2f5 100644
--- a/examples/peerconnection/client/main_wnd.h
+++ b/examples/peerconnection/client/main_wnd.h
@@ -8,19 +8,19 @@
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
-#ifndef WEBRTC_EXAMPLES_PEERCONNECTION_CLIENT_MAIN_WND_H_
-#define WEBRTC_EXAMPLES_PEERCONNECTION_CLIENT_MAIN_WND_H_
+#ifndef EXAMPLES_PEERCONNECTION_CLIENT_MAIN_WND_H_
+#define EXAMPLES_PEERCONNECTION_CLIENT_MAIN_WND_H_
 
 #include <map>
 #include <memory>
 #include <string>
 
-#include "webrtc/api/mediastreaminterface.h"
-#include "webrtc/api/video/video_frame.h"
-#include "webrtc/examples/peerconnection/client/peer_connection_client.h"
-#include "webrtc/media/base/mediachannel.h"
-#include "webrtc/media/base/videocommon.h"
-#include "webrtc/rtc_base/win32.h"
+#include "api/mediastreaminterface.h"
+#include "api/video/video_frame.h"
+#include "examples/peerconnection/client/peer_connection_client.h"
+#include "media/base/mediachannel.h"
+#include "media/base/videocommon.h"
+#include "rtc_base/win32.h"
 
 class MainWndCallback {
  public:
@@ -198,4 +198,4 @@
 };
 #endif  // WIN32
 
-#endif  // WEBRTC_EXAMPLES_PEERCONNECTION_CLIENT_MAIN_WND_H_
+#endif  // EXAMPLES_PEERCONNECTION_CLIENT_MAIN_WND_H_