Add command buffer support for EXT_sRGB_write_control

gpu/command_buffer/service/feature_info.cc

Index: gpu/command_buffer/service/feature_info.cc
diff --git a/gpu/command_buffer/service/feature_info.cc b/gpu/command_buffer/service/feature_info.cc
index 77000c5037eee2a85806b6bb6250b366d81f2f26..cd87ab2aebad6550115babf1bb315cb207bff222 100644
--- a/gpu/command_buffer/service/feature_info.cc
+++ b/gpu/command_buffer/service/feature_info.cc
@@ -572,11 +572,13 @@ void FeatureInfo::InitializeFeatures() {
     validators_.index_type.AddValue(GL_UNSIGNED_INT);
   }
 
+  bool has_srgb_framebuffer_support = false;
   if (gl_version_info_->IsAtLeastGL(3, 2) ||
       (gl_version_info_->IsAtLeastGL(2, 0) &&
        (extensions.Contains("GL_EXT_framebuffer_sRGB") ||
         extensions.Contains("GL_ARB_framebuffer_sRGB")))) {
     feature_flags_.desktop_srgb_support = true;
+    has_srgb_framebuffer_support = true;
   }
   // With EXT_sRGB, unsized SRGB_EXT and SRGB_ALPHA_EXT are accepted by the
   // <format> and <internalformat> parameter of TexImage2D. GLES3 adds support
@@ -599,6 +601,22 @@ void FeatureInfo::InitializeFeatures() {
         GL_FRAMEBUFFER_ATTACHMENT_COLOR_ENCODING_EXT);
     validators_.texture_unsized_internal_format.AddValue(GL_SRGB_EXT);
     validators_.texture_unsized_internal_format.AddValue(GL_SRGB_ALPHA_EXT);
+    has_srgb_framebuffer_support = true;
+  }
+  if (gl_version_info_->is_es3)
+    has_srgb_framebuffer_support = true;
+
+  if (has_srgb_framebuffer_support && !IsWebGLContext()) {
+    // GL_FRAMEBUFFER_SRGB_EXT is exposed by the GLES extension
+    // GL_EXT_sRGB_write_control (which is not part of the core, even in GLES3),
+    // and the desktop extension GL_ARB_framebuffer_sRGB (part of the core in
+    // 3.0).
+    if (feature_flags_.desktop_srgb_support ||
+        extensions.Contains("GL_EXT_sRGB_write_control")) {
+      feature_flags_.ext_srgb_write_control = true;
+      AddExtensionString("GL_EXT_sRGB_write_control");
+      validators_.capability.AddValue(GL_FRAMEBUFFER_SRGB_EXT);
+    }
   }
 
   // On desktop, GL_EXT_texture_sRGB is required regardless of GL version,