Add new helper class to create and synchronize access to SurfaceTextures. The plan is replace the SurfaceTexture in MediaCodecVideoDecoder in a follow-up CL and remove the SurfaceTexture.updateTexImage() call in VideoRendererGui. BUG=webrtc:4993 R=hbos@webrtc.org Review URL: https://codereview.webrtc.org/1342713003 . Cr-Commit-Position: refs/heads/master@{#9938}