Always call DescheduleUntilFinished for WebGL on macOS.

third_party/WebKit/Source/platform/graphics/gpu/DrawingBuffer.cpp

 /*
  * Copyright (c) 2010, Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 286 matching lines @@
     } else {
         m_gl->CopySubTextureCHROMIUM(m_colorBuffer.textureId, frontColorBufferMailbox->textureInfo.textureId,
             0, 0, 0, 0, m_size.width(), m_size.height(), GL_FALSE, GL_FALSE, GL_FALSE);
     }
 
     restoreFramebufferBindings();
     m_contentsChanged = false;
 
     m_gl->ProduceTextureDirectCHROMIUM(frontColorBufferMailbox->textureInfo.textureId, frontColorBufferMailbox->textureInfo.parameters.target, frontColorBufferMailbox->mailbox.name);
     const GLuint64 fenceSync = m_gl->InsertFenceSyncCHROMIUM();
-    if (RuntimeEnabledFeatures::webGLImageChromiumEnabled())
-        m_gl->DescheduleUntilFinishedCHROMIUM();
+#if OS(MACOSX)
+    m_gl->DescheduleUntilFinishedCHROMIUM();
+#endif
     m_gl->Flush();
     m_gl->GenSyncTokenCHROMIUM(fenceSync, frontColorBufferMailbox->mailbox.syncToken);
     frontColorBufferMailbox->mailbox.validSyncToken = true;
     frontColorBufferMailbox->mailbox.allowOverlay = frontColorBufferMailbox->textureInfo.imageId != 0;
     frontColorBufferMailbox->mailbox.textureTarget = frontColorBufferMailbox->textureInfo.parameters.target;
     frontColorBufferMailbox->mailbox.textureSize = WebSize(m_size.width(), m_size.height());
     setBufferClearNeeded(true);
 
     // set m_parentDrawingBuffer to make sure 'this' stays alive as long as it has live mailboxes
     ASSERT(!frontColorBufferMailbox->m_parentDrawingBuffer);
@@ skipping 792 matching lines @@
 
 void DrawingBuffer::restoreTextureBindings()
 {
     // This class potentially modifies the bindings for GL_TEXTURE_2D and
     // GL_TEXTURE_RECTANGLE. Only GL_TEXTURE_2D needs to be restored since
     // the public interface for WebGL does not support GL_TEXTURE_RECTANGLE.
     m_gl->BindTexture(GL_TEXTURE_2D, m_texture2DBinding);
 }
 
 } // namespace blink