gpu: support R16 GPUMemoryBuffer

gpu/command_buffer/client/gles2_implementation.cc

 // 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.
 
 // A class to emulate GLES2 over command buffers.
 
 #include "gpu/command_buffer/client/gles2_implementation.h"
 
 #include <GLES2/gl2.h>
 #include <GLES2/gl2ext.h>
@@ skipping 6212 matching lines @@
     case GL_ATC_RGB_AMD:
     case GL_ATC_RGBA_INTERPOLATED_ALPHA_AMD:
       return capabilities.texture_format_atc;
     case GL_COMPRESSED_RGB_S3TC_DXT1_EXT:
       return capabilities.texture_format_dxt1;
     case GL_COMPRESSED_RGBA_S3TC_DXT5_EXT:
       return capabilities.texture_format_dxt5;
     case GL_ETC1_RGB8_OES:
       return capabilities.texture_format_etc1;
     case GL_RED:
+    case GL_R16_EXT:

[aleksandar.stojiljkovic, 2017/06/08 10:25:03]

As it is not available always, maybe:
  return capabilities.texture_norm16;

e.g.
https://cs.chromium.org/chromium/src/media/renderers/skcanvas_video_renderer....

[riju_, 2017/06/09 08:20:10]

Done.

     case GL_RG_EXT:
     case GL_RGB:
     case GL_RGBA:
     case GL_RGB_YCBCR_422_CHROMIUM:
     case GL_RGB_YCBCR_420V_CHROMIUM:
     case GL_RGB_YCRCB_420_CHROMIUM:
     case GL_BGRA_EXT:
       return true;
     default:
       return false;
@@ skipping 866 matching lines @@
   CheckGLError();
 }
 
 // Include the auto-generated part of this file. We split this because it means
 // we can easily edit the non-auto generated parts right here in this file
 // instead of having to edit some template or the code generator.
 #include "gpu/command_buffer/client/gles2_implementation_impl_autogen.h"
 
 }  // namespace gles2
 }  // namespace gpu