Fix darkened pixels when rendering using GPU

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 32e72c69f32652768c47c267509af2b3df97b8d9..1d247d7640638f0f2672765ba76a039941e8e6ae 100644
--- a/gpu/command_buffer/service/feature_info.cc
+++ b/gpu/command_buffer/service/feature_info.cc
@@ -685,12 +685,6 @@ void FeatureInfo::InitializeFeatures() {
     }
   }
 
-  // The extension GL_EXT_texture_sRGB_decode is the same on desktop and GLES.
-  if (extensions.Contains("GL_EXT_texture_sRGB_decode") && !IsWebGLContext()) {
-    AddExtensionString("GL_EXT_texture_sRGB_decode");
-    validators_.texture_parameter.AddValue(GL_TEXTURE_SRGB_DECODE_EXT);
-  }

[Ken Russell (switch to Gerrit), 2017/04/25 16:15:01]

Simply stopping the command buffer from advertising the
GL_EXT_texture_sRGB_decode extension to the renderer processes is not the
correct fix. Clearly there is an unexpected problem with the *usage* of this
extension and that's what needs to be fixed. Otherwise for example when more of
Skia is moved to the GPU process this same bug will happen again.

As far as I can tell the only use of this extension in Chrome's code base is in
Skia's Ganesh backend:
https://cs.chromium.org/chromium/src/third_party/skia/src/gpu/gl/GrGLGpu.cpp?...

You should work with the Skia team to understand why double-gamma-correction is
happening during putImageData operations. +bsalomon

Also, you could consider adding an entry to
src/gpu/config/gpu_driver_bug_list.json which uses the disabled_extensions
section to disable the GL_EXT_texture_sRGB_decode extension, referring to one or
more of these bugs, with the intent to remove the bug entry as soon as the root
cause is known and fixed.

[zakerinasab, 2017/04/25 16:45:46]

Done.

-
   bool have_s3tc_srgb = false;
   if (gl_version_info_->is_es) {
     // On mobile, the only extension that supports S3TC+sRGB is NV_sRGB_formats.