Nil out EAGLContext explicitly on RTCEAGLVideoView dealloc.

webrtc/sdk/objc/Framework/Classes/RTCEAGLVideoView.m

 /*
  *  Copyright 2015 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 75 matching lines @@
 @interface RTCEAGLVideoView () <GLKViewDelegate>
 // |videoFrame| is set when we receive a frame from a worker thread and is read
 // from the display link callback so atomicity is required.
 @property(atomic, strong) RTCVideoFrame *videoFrame;
 @property(nonatomic, readonly) GLKView *glkView;
 @property(nonatomic, readonly) RTCOpenGLVideoRenderer *glRenderer;
 @end
 
 @implementation RTCEAGLVideoView {
   RTCDisplayLinkTimer *_timer;
+  EAGLContext *_glContext;
   // This flag should only be set and read on the main thread (e.g. by
   // setNeedsDisplay)
   BOOL _isDirty;
 }
 
 @synthesize delegate = _delegate;
 @synthesize videoFrame = _videoFrame;
 @synthesize glkView = _glkView;
 @synthesize glRenderer = _glRenderer;
 
@@ skipping 10 matching lines @@
   }
   return self;
 }
 
 - (void)configure {
   EAGLContext *glContext =
     [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES3];
   if (!glContext) {
     glContext = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES2];
   }
-  _glRenderer = [[RTCOpenGLVideoRenderer alloc] initWithContext:glContext];
+  _glContext = glContext;
+  _glRenderer = [[RTCOpenGLVideoRenderer alloc] initWithContext:_glContext];
 
   // GLKView manages a framebuffer for us.
   _glkView = [[GLKView alloc] initWithFrame:CGRectZero
-                                    context:glContext];
+                                    context:_glContext];
   _glkView.drawableColorFormat = GLKViewDrawableColorFormatRGBA8888;
   _glkView.drawableDepthFormat = GLKViewDrawableDepthFormatNone;
   _glkView.drawableStencilFormat = GLKViewDrawableStencilFormatNone;
   _glkView.drawableMultisample = GLKViewDrawableMultisampleNone;
   _glkView.delegate = self;
   _glkView.layer.masksToBounds = YES;
   _glkView.enableSetNeedsDisplay = NO;
   [self addSubview:_glkView];
 
   // Listen to application state in order to clean up OpenGL before app goes
@@ skipping 21 matching lines @@
 }
 
 - (void)dealloc {
   [[NSNotificationCenter defaultCenter] removeObserver:self];
   UIApplicationState appState =
       [UIApplication sharedApplication].applicationState;
   if (appState == UIApplicationStateActive) {
     [self teardownGL];
   }
   [_timer invalidate];
+  if (_glContext && [EAGLContext currentContext] == _glContext) {
+    [EAGLContext setCurrentContext:nil];
+  }
 }
 
 #pragma mark - UIView
 
 - (void)setNeedsDisplay {
   [super setNeedsDisplay];
   _isDirty = YES;
 }
 
 - (void)setNeedsDisplayInRect:(CGRect)rect {
@@ skipping 74 matching lines @@
 
 - (void)didBecomeActive {
   [self setupGL];
 }
 
 - (void)willResignActive {
   [self teardownGL];
 }
 
 @end