SRGB_EXT is a valid format of texture in WebGL1.0 and ES2.0 contexts

gpu/command_buffer/service/feature_info.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.
 
 #include "gpu/command_buffer/service/feature_info.h"
 
 #include <stddef.h>
 
 #include <set>
 #include <vector>
@@ skipping 593 matching lines @@
        extensions.Contains("GL_EXT_sRGB")) ||
       gfx::HasDesktopGLFeatures()) {
     AddExtensionString("GL_EXT_sRGB");
     validators_.texture_internal_format.AddValue(GL_SRGB_EXT);
     validators_.texture_internal_format.AddValue(GL_SRGB_ALPHA_EXT);
     validators_.texture_format.AddValue(GL_SRGB_EXT);
     validators_.texture_format.AddValue(GL_SRGB_ALPHA_EXT);
     validators_.render_buffer_format.AddValue(GL_SRGB8_ALPHA8_EXT);
     validators_.frame_buffer_parameter.AddValue(
         GL_FRAMEBUFFER_ATTACHMENT_COLOR_ENCODING_EXT);
+    validators_.texture_unsized_internal_format.AddValue(GL_SRGB_EXT);

[yunchao, 2016/04/12 07:21:34]

This ext has been added into texture_internal_format and texture_format. Why it
needs to be added into texture_unsized_internal_format? Is there any test case? 

[qiankun, 2016/04/12 11:01:50]

GLES extension spec can be found at
https://www.khronos.org/registry/gles/extensions/EXT/EXT_sRGB.txt. It is based
on gles2: 
"Modify Section 3.7.1, Texture Image Specification:

    Add 2 new rows to Table 3.3

        SRGB_EXT             R, G, B        Color
        SRGB_ALPHA_EXT       R, G, B, A     Color

    Add 2 new rows to Table 3.4
    
        SRGB_EXT           UNSIGNED_BYTE     3
        SRGB_ALPHA_EXT     UNSIGNED_BYTE     4
"
So map to gles3, SRGB_EXT should be added to table 3.3 in
https://www.khronos.org/registry/gles/specs/3.0/es_spec_3.0.4.pdf.

     validators_.texture_unsized_internal_format.AddValue(GL_SRGB_ALPHA_EXT);
   }
 
   bool enable_texture_format_bgra8888 = false;
   bool enable_read_format_bgra = false;
   bool enable_render_buffer_bgra = false;
   bool enable_immutable_texture_format_bgra_on_es3 =
       extensions.Contains("GL_APPLE_texture_format_BGRA8888");
 
   // Check if we should allow GL_EXT_texture_format_BGRA8888
@@ skipping 800 matching lines @@
   if (pos == std::string::npos) {
     extensions_ += (extensions_.empty() ? "" : " ") + str;
   }
 }
 
 FeatureInfo::~FeatureInfo() {
 }
 
 }  // namespace gles2
 }  // namespace gpu