Reland cmaa, gpu: use R8 image texture when GL_NV_image_formats is available.

gpu/command_buffer/service/gles2_cmd_apply_framebuffer_attachment_cmaa_intel.h

 // Copyright 2016 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 GPU_COMMAND_BUFFER_SERVICE_GLES2_CMD_APPLY_FRAMEBUFFER_ATTACHMENT_CMAA_INTEL_H_
 #define GPU_COMMAND_BUFFER_SERVICE_GLES2_CMD_APPLY_FRAMEBUFFER_ATTACHMENT_CMAA_INTEL_H_
 
 #include "gpu/command_buffer/service/gl_utils.h"
 #include "gpu/gpu_export.h"
 
@@ skipping 39 matching lines @@
   GLuint CreateProgram(const char* defines,
                        const char* vs_source,
                        const char* fs_source);
   GLuint CreateShader(GLenum type, const char* defines, const char* source);
 
   bool initialized_;
   bool textures_initialized_;
   bool is_in_gamma_correct_mode_;
   bool supports_usampler_;
   bool supports_r8_image_;
-  bool supports_r8_read_format_;
   bool is_gles31_compatible_;
 
   int frame_id_;
 
   GLint width_;
   GLint height_;
 
   GLuint edges0_shader_;
   GLuint edges1_shader_;
   GLuint edges_combine_shader_;
@@ skipping 19 matching lines @@
   static const char cmaa_frag_s1_[];
   static const char cmaa_frag_s2_[];
 
   DISALLOW_COPY_AND_ASSIGN(ApplyFramebufferAttachmentCMAAINTELResourceManager);
 };
 
 }  // namespace gles2
 }  // namespace gpu
 
 #endif  // GPU_COMMAND_BUFFER_SERVICE_GLES2_CMD_APPLY_FRAMEBUFFER_ATTACHMENT_CMAA_INTEL_H_