Fix "unused variable" warnings.

media/gpu/avda_codec_image.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MEDIA_GPU_AVDA_CODEC_IMAGE_H_
 #define MEDIA_GPU_AVDA_CODEC_IMAGE_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 131 matching lines @@
 
   // May be null.
   media::MediaCodecBridge* media_codec_;
 
   const base::WeakPtr<gpu::gles2::GLES2Decoder> decoder_;
 
   // The SurfaceTexture to render to. This is null when rendering to a
   // SurfaceView.
   const scoped_refptr<gfx::SurfaceTexture> surface_texture_;
 
-  // Should we detach |surface_texture_| from its GL context when we are
-  // deleted?  This happens when it's using our Texture's texture handle.
-  bool detach_surface_texture_on_destruction_;
-
   // The texture that we're attached to.
   gpu::gles2::Texture* texture_;
 
   // Texture matrix of the front buffer of the surface texture.
   float gl_matrix_[16];
 
   // The picture buffer id attached to this image.
   int picture_buffer_id_;
 
   DISALLOW_COPY_AND_ASSIGN(AVDACodecImage);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_GPU_AVDA_CODEC_IMAGE_H_