Android EGL: Synchronize calls to eglSwapBuffers and eglMakeCurrent

webrtc/api/java/android/org/webrtc/SurfaceTextureHelper.java

 /*
  *  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 432 matching lines @@
   private void tryDeliverTextureFrame() {
     if (handler.getLooper().getThread() != Thread.currentThread()) {
       throw new IllegalStateException("Wrong thread.");
     }
     if (isQuitting || !hasPendingTexture || isTextureInUse || listener == null) {
       return;
     }
     isTextureInUse = true;
     hasPendingTexture = false;
 
-    eglBase.makeCurrent();
-    surfaceTexture.updateTexImage();
+    // SurfaceTexture.updateTexImage apparently can compete and deadlock with eglSwapBuffers,
+    // as observed on Nexus 5. Therefore, synchronize it with the EGL functions.
+    // See https://bugs.chromium.org/p/webrtc/issues/detail?id=5702 for more info.
+    synchronized (EglBase.lock) {
+      surfaceTexture.updateTexImage();
+    }
 
     final float[] transformMatrix = new float[16];
     surfaceTexture.getTransformMatrix(transformMatrix);
     final long timestampNs = (Build.VERSION.SDK_INT >= Build.VERSION_CODES.ICE_CREAM_SANDWICH)
         ? surfaceTexture.getTimestamp()
         : TimeUnit.MILLISECONDS.toNanos(SystemClock.elapsedRealtime());
     listener.onTextureFrameAvailable(oesTextureId, transformMatrix, timestampNs);
   }
 
   private void release() {
     if (handler.getLooper().getThread() != Thread.currentThread()) {
       throw new IllegalStateException("Wrong thread.");
     }
     if (isTextureInUse || !isQuitting) {
       throw new IllegalStateException("Unexpected release.");
     }
     synchronized (this) {
       if (yuvConverter != null)
         yuvConverter.release();
     }
-    eglBase.makeCurrent();
     GLES20.glDeleteTextures(1, new int[] {oesTextureId}, 0);
     surfaceTexture.release();
     eglBase.release();
     handler.getLooper().quit();
   }
 }