gpu: Add ARB_occlusion_query support.

gpu/command_buffer/service/feature_info.cc

 // 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.
 
 #include "gpu/command_buffer/service/feature_info.h"
 
 #include <stddef.h>
 
 #include <set>
 #include <vector>
@@ skipping 111 matching lines @@
       oes_depth24(false),
       oes_compressed_etc1_rgb8_texture(false),
       packed_depth24_stencil8(false),
       npot_ok(false),
       enable_texture_float_linear(false),
       enable_texture_half_float_linear(false),
       angle_translated_shader_source(false),
       angle_pack_reverse_row_order(false),
       arb_texture_rectangle(false),
       angle_instanced_arrays(false),
+      occlusion_query(false),
       occlusion_query_boolean(false),
       use_arb_occlusion_query2_for_occlusion_query_boolean(false),
       use_arb_occlusion_query_for_occlusion_query_boolean(false),
       native_vertex_array_object(false),
       ext_texture_format_astc(false),
       ext_texture_format_atc(false),
       ext_texture_format_bgra8888(false),
       ext_texture_format_dxt1(false),
       ext_texture_format_dxt5(false),
       enable_shader_name_hashing(false),
@@ skipping 1030 matching lines @@
       extensions.Contains("GL_EXT_occlusion_query_boolean");
   bool have_arb_occlusion_query2 =
       extensions.Contains("GL_ARB_occlusion_query2");
   bool have_arb_occlusion_query =
       extensions.Contains("GL_ARB_occlusion_query");
 
   if (have_occlusion_query ||
       have_ext_occlusion_query_boolean ||
       have_arb_occlusion_query2 ||
       have_arb_occlusion_query) {
+    feature_flags_.occlusion_query = have_arb_occlusion_query;

[jbauman, 2017/01/19 01:33:43]

I think this was promoted to core in OpenGL 1.5 (desktop), so you should check
for that as well.

[reveman, 2017/01/19 04:44:34]

Good call. Added it to the have_arb_occlusion_query check in latest patch.

     if (context_type_ == CONTEXT_TYPE_OPENGLES2) {
       AddExtensionString("GL_EXT_occlusion_query_boolean");
     }
     feature_flags_.occlusion_query_boolean = true;
     feature_flags_.use_arb_occlusion_query2_for_occlusion_query_boolean =
         !have_ext_occlusion_query_boolean && (have_arb_occlusion_query2 ||
         (gl_version_info_->IsAtLeastGL(3, 3) &&
          gl_version_info_->IsLowerThanGL(4, 3)));
     feature_flags_.use_arb_occlusion_query_for_occlusion_query_boolean =
         !have_ext_occlusion_query_boolean && have_arb_occlusion_query &&
@@ skipping 396 matching lines @@
   if (pos == std::string::npos) {
     extensions_ += (extensions_.empty() ? "" : " ") + str;
   }
 }
 
 FeatureInfo::~FeatureInfo() {
 }
 
 }  // namespace gles2
 }  // namespace gpu