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/modules/audio_device/audio_device_impl.h b/modules/audio_device/audio_device_impl.h
index 69e32d4..77c4cc5 100644
--- a/modules/audio_device/audio_device_impl.h
+++ b/modules/audio_device/audio_device_impl.h
@@ -8,17 +8,17 @@
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
-#ifndef WEBRTC_AUDIO_DEVICE_AUDIO_DEVICE_IMPL_H
-#define WEBRTC_AUDIO_DEVICE_AUDIO_DEVICE_IMPL_H
+#ifndef AUDIO_DEVICE_AUDIO_DEVICE_IMPL_H_
+#define AUDIO_DEVICE_AUDIO_DEVICE_IMPL_H_
 
 #if defined(WEBRTC_INCLUDE_INTERNAL_AUDIO_DEVICE)
 
 #include <memory>
 
-#include "webrtc/modules/audio_device/audio_device_buffer.h"
-#include "webrtc/modules/audio_device/include/audio_device.h"
-#include "webrtc/rtc_base/checks.h"
-#include "webrtc/rtc_base/criticalsection.h"
+#include "modules/audio_device/audio_device_buffer.h"
+#include "modules/audio_device/include/audio_device.h"
+#include "rtc_base/checks.h"
+#include "rtc_base/criticalsection.h"
 
 namespace webrtc {
 
@@ -201,4 +201,4 @@
 
 #endif  // defined(WEBRTC_INCLUDE_INTERNAL_AUDIO_DEVICE)
 
-#endif  // WEBRTC_MODULES_INTERFACE_AUDIO_DEVICE_IMPL_H_
+#endif  // MODULES_INTERFACE_AUDIO_DEVICE_IMPL_H_