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

gpu/command_buffer/service/gles2_cmd_decoder_passthrough.h

Index: gpu/command_buffer/service/gles2_cmd_decoder_passthrough.h
diff --git a/gpu/command_buffer/service/gles2_cmd_decoder_passthrough.h b/gpu/command_buffer/service/gles2_cmd_decoder_passthrough.h
index 0193b4aa35b665c8ab5f2415686367ec3f2ea813..2b56bbf5f407c752635d45be1966a5067b2d317a 100644
--- a/gpu/command_buffer/service/gles2_cmd_decoder_passthrough.h
+++ b/gpu/command_buffer/service/gles2_cmd_decoder_passthrough.h
@@ -287,6 +287,8 @@ class GLES2DecoderPassthroughImpl : public GLES2Decoder {
 
   void UpdateTextureBinding(GLenum target, GLuint client_id, GLuint service_id);
 
+  void InitializeNativeCaps();
+
   int commands_to_process_;
 
   DebugMarkerManager debug_marker_manager_;
@@ -377,6 +379,14 @@ class GLES2DecoderPassthroughImpl : public GLES2Decoder {
 
   std::set<GLenum> errors_;
 
+  // Native caps
+  bool has_es3_;
+  bool has_ext_discard_framebuffer_;
+  bool has_angle_framebuffer_multisample_;
+  bool has_ext_disjoint_timer_query_;
+  bool has_chromium_copy_texture_;
+  bool has_chromium_copy_compressed_texture_;

[Zhenyao Mo, 2017/02/13 18:12:08]

Can we consolidate these to FeatureInfo? It seems to be a better place for these
caps.

[Geoff Lang, 2017/02/13 19:53:06]

I tried but these features are enabled sometimes when the extension doesn't
exist.  For example, the FeatureInfo says that ext_discard_framebuffer is
present when the native extension exists or it's on es3 because it knows it can
be emulated.  I need to do a little extra tracking to know which native function
to call.

+
   // Cache of scratch memory
   std::vector<uint8_t> scratch_memory_;