Remove unsafe mode to enable es3 api by default for WebGL2 and ES3 context

gpu/command_buffer/service/gpu_preferences.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef GPU_COMMAND_BUFFER_SERVICE_GPU_PREFERENCES_H_
 #define GPU_COMMAND_BUFFER_SERVICE_GPU_PREFERENCES_H_
 
 #include <stddef.h>
 
 #include "base/macros.h"
@@ skipping 113 matching lines @@
 
   // ===================================
   // Settings from //ui/gl/gl_switches.h
 
   // Turns on GPU logging (debug build only).
   bool enable_gpu_service_logging = false;
 
   // Turns on calling TRACE for every GL call.
   bool enable_gpu_service_tracing = false;
 
-  // Enable OpenGL ES 3 APIs without proper service side validation.
-  bool enable_unsafe_es3_apis = false;
-
   // Use the Pass-through command decoder, skipping all validation and state
   // tracking.
   bool use_passthrough_cmd_decoder = false;
 };
 
 }  // namespace gpu
 
 #endif // GPU_COMMAND_BUFFER_SERVICE_GPU_PREFERENCES_H_