Check for some extensions before calling potentially NULL GL entry points.

gpu/command_buffer/service/feature_info.h

 // Copyright (c) 2012 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_FEATURE_INFO_H_
 #define GPU_COMMAND_BUFFER_SERVICE_FEATURE_INFO_H_
 
 #include <memory>
 #include <string>
 
@@ skipping 84 matching lines @@
     bool desktop_srgb_support = false;
     bool arb_es3_compatibility = false;
     bool chromium_color_buffer_float_rgb = false;
     bool chromium_color_buffer_float_rgba = false;
     bool angle_robust_client_memory = false;
     bool khr_debug = false;
     bool chromium_bind_generates_resource = false;
     bool angle_webgl_compatibility = false;
     bool ext_srgb_write_control = false;
     bool ext_srgb = false;
+    bool chromium_copy_texture = false;
+    bool chromium_copy_compressed_texture = false;
+    bool angle_framebuffer_multisample = false;
+    bool ext_disjoint_timer_query = false;
   };
 
   FeatureInfo();
 
   // Constructor with workarounds taken from the current process's CommandLine
   explicit FeatureInfo(
       const GpuDriverBugWorkarounds& gpu_driver_bug_workarounds);
 
   // Constructor with workarounds taken from |command_line|.
   FeatureInfo(const base::CommandLine& command_line,
@@ skipping 90 matching lines @@
   bool disable_shader_translator_;
   std::unique_ptr<gl::GLVersionInfo> gl_version_info_;
 
   DISALLOW_COPY_AND_ASSIGN(FeatureInfo);
 };
 
 }  // namespace gles2
 }  // namespace gpu
 
 #endif  // GPU_COMMAND_BUFFER_SERVICE_FEATURE_INFO_H_