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/sdk/objc/Framework/Classes/VideoToolbox/RTCVideoEncoderH264.mm b/sdk/objc/Framework/Classes/VideoToolbox/RTCVideoEncoderH264.mm
index 6e2b568..a42cc97 100644
--- a/sdk/objc/Framework/Classes/VideoToolbox/RTCVideoEncoderH264.mm
+++ b/sdk/objc/Framework/Classes/VideoToolbox/RTCVideoEncoderH264.mm
@@ -24,16 +24,16 @@
 #import "WebRTC/RTCVideoFrameBuffer.h"
 #import "helpers.h"
 #include "libyuv/convert_from.h"
-#include "webrtc/common_video/h264/h264_bitstream_parser.h"
-#include "webrtc/common_video/h264/profile_level_id.h"
-#include "webrtc/common_video/include/bitrate_adjuster.h"
-#include "webrtc/modules/include/module_common_types.h"
-#include "webrtc/modules/video_coding/include/video_error_codes.h"
-#include "webrtc/rtc_base/buffer.h"
-#include "webrtc/rtc_base/logging.h"
-#include "webrtc/rtc_base/timeutils.h"
-#include "webrtc/sdk/objc/Framework/Classes/VideoToolbox/nalu_rewriter.h"
-#include "webrtc/system_wrappers/include/clock.h"
+#include "common_video/h264/h264_bitstream_parser.h"
+#include "common_video/h264/profile_level_id.h"
+#include "common_video/include/bitrate_adjuster.h"
+#include "modules/include/module_common_types.h"
+#include "modules/video_coding/include/video_error_codes.h"
+#include "rtc_base/buffer.h"
+#include "rtc_base/logging.h"
+#include "rtc_base/timeutils.h"
+#include "sdk/objc/Framework/Classes/VideoToolbox/nalu_rewriter.h"
+#include "system_wrappers/include/clock.h"
 
 @interface RTCVideoEncoderH264 ()