gpu: check GL_RGB565 work in ES3 context

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 0ad77686904d7d959e50cde34355312caa9e9a84..cb679997a0bd3568720c288261da7e8b4b967051 100644
--- a/gpu/command_buffer/service/feature_info.cc
+++ b/gpu/command_buffer/service/feature_info.cc
@@ -1407,6 +1407,8 @@ void FeatureInfo::InitializeFeatures() {
 }
 
 bool FeatureInfo::IsES3Capable() const {
+  if (testing_es3_apis_enabled_)
+    return true;
   if (!enable_unsafe_es3_apis_switch_)
     return false;
   if (workarounds_.disable_texture_storage)
@@ -1416,6 +1418,11 @@ bool FeatureInfo::IsES3Capable() const {
   return false;
 }
 
+void FeatureInfo::EnableES3ValidatorsForTesting() {
+  testing_es3_apis_enabled_ = true;
+  EnableES3Validators();
+}
+
 void FeatureInfo::EnableES3Validators() {
   DCHECK(IsES3Capable());
   validators_.UpdateValuesES3();