Emulate GL_PRIMITIVE_RESTART_FIXED_INDEX: part I

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 04a9eb25443cb2a25d52400ba714c850ea63eca6..98d2185dcd91713071dbbd425196f4ec44ace57a 100644
--- a/gpu/command_buffer/service/gles2_cmd_decoder.cc
+++ b/gpu/command_buffer/service/gles2_cmd_decoder.cc
@@ -7056,6 +7056,9 @@ error::Error GLES2DecoderImpl::DoDrawArrays(
 
 error::Error GLES2DecoderImpl::HandleDrawArrays(uint32 immediate_data_size,
                                                 const void* cmd_data) {
+  // TODO(zmo): crbug.com/481184
+  // On Desktop GL with versions lower than 4.3, we need to emulate
+  // GL_PRIMITIVE_RESTART_FIXED_INDEX using glPrimitiveRestartIndex().
   const cmds::DrawArrays& c = *static_cast<const cmds::DrawArrays*>(cmd_data);
   return DoDrawArrays("glDrawArrays",
                       false,
@@ -7199,6 +7202,9 @@ error::Error GLES2DecoderImpl::DoDrawElements(
 
 error::Error GLES2DecoderImpl::HandleDrawElements(uint32 immediate_data_size,
                                                   const void* cmd_data) {
+  // TODO(zmo): crbug.com/481184
+  // On Desktop GL with versions lower than 4.3, we need to emulate
+  // GL_PRIMITIVE_RESTART_FIXED_INDEX using glPrimitiveRestartIndex().
   const gles2::cmds::DrawElements& c =
       *static_cast<const gles2::cmds::DrawElements*>(cmd_data);
   return DoDrawElements("glDrawElements",