From 6144fa53629c821f42b37b32efc74ad86ad5fedf Mon Sep 17 00:00:00 2001
From: JT Teh <jtteh@webrtc.org>
Date: Tue, 10 Apr 2018 00:27:04 +0000
Subject: [PATCH] Revert "Improve thread-safety of MTL Renderer."
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This reverts commit a8f13ccad400eb8ff84a379042c0595951ca9658.

Reason for revert: It's causing no video to be shown after the 1st call.

Original change's description:
> Improve thread-safety of MTL Renderer.
>
> Bug: b/77579859
> Change-Id: I427d0f41593155dc5cbf98a09d7ec826497b803c
> Reviewed-on: https://webrtc-review.googlesource.com/67040
> Commit-Queue: Kári Helgason <kthelgason@webrtc.org>
> Reviewed-by: Anders Carlsson <andersc@webrtc.org>
> Cr-Commit-Position: refs/heads/master@{#22795}

TBR=andersc@webrtc.org,kthelgason@webrtc.org

Change-Id: Ia8f33995e087178f1c3be7753f70be8ba18447f8
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: b/77579859
Reviewed-on: https://webrtc-review.googlesource.com/68860
Reviewed-by: JT Teh <jtteh@webrtc.org>
Commit-Queue: JT Teh <jtteh@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#22800}
---
 .../Classes/Metal/RTCMTLNV12Renderer.mm       |  2 --
 .../Framework/Classes/Metal/RTCMTLVideoView.m | 22 +++++++++----------
 2 files changed, 11 insertions(+), 13 deletions(-)

diff --git a/sdk/objc/Framework/Classes/Metal/RTCMTLNV12Renderer.mm b/sdk/objc/Framework/Classes/Metal/RTCMTLNV12Renderer.mm
index 6de9c347e6..079b5fb76c 100644
--- a/sdk/objc/Framework/Classes/Metal/RTCMTLNV12Renderer.mm
+++ b/sdk/objc/Framework/Classes/Metal/RTCMTLNV12Renderer.mm
@@ -18,7 +18,6 @@
 #import "WebRTC/RTCVideoFrameBuffer.h"
 
 #import "RTCMTLRenderer+Private.h"
-#include "rtc_base/checks.h"
 
 #define MTL_STRINGIFY(s) @ #s
 
@@ -86,7 +85,6 @@ static NSString *const shaderSource = MTL_STRINGIFY(
 }
 
 - (BOOL)setupTexturesForFrame:(nonnull RTCVideoFrame *)frame {
-  RTC_DCHECK([frame.buffer isKindOfClass:[RTCCVPixelBuffer class]]);
   [super setupTexturesForFrame:frame];
   CVPixelBufferRef pixelBuffer = ((RTCCVPixelBuffer *)frame.buffer).pixelBuffer;
 
diff --git a/sdk/objc/Framework/Classes/Metal/RTCMTLVideoView.m b/sdk/objc/Framework/Classes/Metal/RTCMTLVideoView.m
index e343bb48b4..0e17777c4a 100644
--- a/sdk/objc/Framework/Classes/Metal/RTCMTLVideoView.m
+++ b/sdk/objc/Framework/Classes/Metal/RTCMTLVideoView.m
@@ -105,32 +105,32 @@
 
 - (void)drawInMTKView:(nonnull MTKView *)view {
   NSAssert(view == self.metalView, @"Receiving draw callbacks from foreign instance.");
-  RTCVideoFrame *videoFrame = self.videoFrame;
-  if (!videoFrame) {
+  if (!self.videoFrame) {
     return;
   }
 
-  if ([videoFrame.buffer isKindOfClass:[RTCCVPixelBuffer class]]) {
-    static dispatch_once_t nv12_token;
-    dispatch_once(&nv12_token, ^{
+  id<RTCMTLRenderer> renderer = nil;
+  if ([self.videoFrame.buffer isKindOfClass:[RTCCVPixelBuffer class]]) {
+    if (!self.rendererNV12) {
       self.rendererNV12 = [RTCMTLVideoView createNV12Renderer];
       if (![self.rendererNV12 addRenderingDestination:self.metalView]) {
         self.rendererNV12 = nil;
         RTCLogError(@"Failed to create NV12 renderer");
       }
-    });
-    [self.rendererNV12 drawFrame:videoFrame];
+    }
+    renderer = self.rendererNV12;
   } else {
-    static dispatch_once_t i420_token;
-    dispatch_once(&i420_token, ^{
+    if (!self.rendererI420) {
       self.rendererI420 = [RTCMTLVideoView createI420Renderer];
       if (![self.rendererI420 addRenderingDestination:self.metalView]) {
         self.rendererI420 = nil;
         RTCLogError(@"Failed to create I420 renderer");
       }
-    });
-    [self.rendererI420 drawFrame:videoFrame];
+    }
+    renderer = self.rendererI420;
   }
+
+  [renderer drawFrame:self.videoFrame];
 }
 
 - (void)mtkView:(MTKView *)view drawableSizeWillChange:(CGSize)size {