Turn on FRAMEBUFFER_SRGB on desktop GL.

gpu/command_buffer/service/gles2_cmd_decoder.cc

Index: gpu/command_buffer/service/gles2_cmd_decoder.cc
diff --git a/gpu/command_buffer/service/gles2_cmd_decoder.cc b/gpu/command_buffer/service/gles2_cmd_decoder.cc
index affed33b0e82a8399fc076eb5e414d73e347da4a..0f9bc4d3a7df26e424c8d44582f4ad7a0723b0f9 100644
--- a/gpu/command_buffer/service/gles2_cmd_decoder.cc
+++ b/gpu/command_buffer/service/gles2_cmd_decoder.cc
@@ -3034,6 +3034,14 @@ bool GLES2DecoderImpl::Initialize(const scoped_refptr<gfx::GLSurface>& surface,
     glEnable(GL_TEXTURE_CUBE_MAP_SEAMLESS);
   }
 
+  // ES3 requires sRGB-linear color space conversion if
+  // FRAMEBUFFER_ATTACHMENT_COLOR_ENCODING for a buffer is sRGB, for situations
+  // like blending, clearing, etc.
+  // On Desktop GL, this is not enabled by default.
+  if (feature_info_->gl_version_info().IsAtLeastGL(3, 2)) {
+    glEnable(GL_FRAMEBUFFER_SRGB);
+  }
+
   has_robustness_extension_ =
       context->HasExtension("GL_ARB_robustness") ||
       context->HasExtension("GL_KHR_robustness") ||