command_buffer_gles2: Implement EGL default Display as a global object

gpu/command_buffer/service/gles2_cmd_decoder.h

 // Copyright (c) 2012 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.
 
 // This file contains the GLES2Decoder class.
 
 #ifndef GPU_COMMAND_BUFFER_SERVICE_GLES2_CMD_DECODER_H_
 #define GPU_COMMAND_BUFFER_SERVICE_GLES2_CMD_DECODER_H_
 
 #include <stdint.h>
@@ skipping 140 matching lines @@
                           bool offscreen,
                           const gfx::Size& offscreen_size,
                           const DisallowedFeatures& disallowed_features,
                           const std::vector<int32_t>& attribs) = 0;
 
   // Destroys the graphics context.
   virtual void Destroy(bool have_context) = 0;
 
   // Set the surface associated with the default FBO.
   virtual void SetSurface(const scoped_refptr<gfx::GLSurface>& surface) = 0;
+  // Releases the surface associated with the GL context.
+  // The decoder should not be used until a new surface is set.
+  virtual void ReleaseSurface() = 0;
 
   virtual void ProduceFrontBuffer(const Mailbox& mailbox) = 0;
 
   // Resize an offscreen frame buffer.
   virtual bool ResizeOffscreenFrameBuffer(const gfx::Size& size) = 0;
 
   // Make this decoder's GL context current.
   virtual bool MakeCurrent() = 0;
 
   // Gets the GLES2 Util which holds info.
@@ skipping 143 matching lines @@
   bool log_commands_;
   bool unsafe_es3_apis_enabled_;
   bool force_shader_name_hashing_for_test_;
   DISALLOW_COPY_AND_ASSIGN(GLES2Decoder);
 };
 
 }  // namespace gles2
 }  // namespace gpu
 
 #endif  // GPU_COMMAND_BUFFER_SERVICE_GLES2_CMD_DECODER_H_