Add support for GL_COMMANDS_ISSUED_CHROMIUM fence like query.

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 <set>
 
 #include "base/string_number_conversions.h"
 #include "gpu/command_buffer/service/gl_utils.h"
@@ skipping 100 matching lines @@
 
   bool npot_ok = false;
 
   AddExtensionString("GL_CHROMIUM_resource_safe");
   AddExtensionString("GL_CHROMIUM_resize");
   AddExtensionString("GL_CHROMIUM_strict_attribs");
   AddExtensionString("GL_CHROMIUM_swapbuffers_complete_callback");
   AddExtensionString("GL_CHROMIUM_rate_limit_offscreen_context");
   AddExtensionString("GL_CHROMIUM_set_visibility");
   AddExtensionString("GL_CHROMIUM_gpu_memory_manager");
+  AddExtensionString("GL_CHROMIUM_command_buffer_query");
   AddExtensionString("GL_ANGLE_translated_shader_source");
 
   if (ext.Have("GL_ANGLE_translated_shader_source")) {
     feature_flags_.angle_translated_shader_source = true;
   }
 
   // Only turn this feature on if it is requested. Not by default.
   if (desired_features && ext.Desire("GL_CHROMIUM_webglsl")) {
     AddExtensionString("GL_CHROMIUM_webglsl");
     feature_flags_.chromium_webglsl = true;
@@ skipping 301 matching lines @@
         validators_.texture_internal_format_storage.AddValue(GL_RGBA16F_EXT);
         validators_.texture_internal_format_storage.AddValue(GL_RGB16F_EXT);
         validators_.texture_internal_format_storage.AddValue(GL_ALPHA16F_EXT);
         validators_.texture_internal_format_storage.AddValue(
             GL_LUMINANCE16F_EXT);
         validators_.texture_internal_format_storage.AddValue(
             GL_LUMINANCE_ALPHA16F_EXT);
     }
   }
 
+  bool have_ext_occlusion_query_boolean =
+      ext.Have("GL_EXT_occlusion_query_boolean");
+  bool have_arb_occlusion_query2 = ext.Have("GL_ARB_occlusion_query2");
   if (ext.Desire("GL_EXT_occlusion_query_boolean") &&
-      (ext.Have("GL_EXT_occlusion_query_boolean") ||
-       ext.Have("GL_ARB_occlusion_query2"))) {
-    // TODO(gman): Comment in the next line once this really works.
-    // AddExtensionString("GL_EXT_occlusion_query_boolean");
+      (have_ext_occlusion_query_boolean || have_arb_occlusion_query2)) {
+    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;
   }
 
   if (ext.Desire("GL_ANGLE_instanced_arrays") &&
       (ext.Have("GL_ANGLE_instanced_arrays") ||
        (ext.Have("GL_ARB_instanced_arrays") &&
         ext.Have("GL_ARB_draw_instanced")))) {
     AddExtensionString("GL_ANGLE_instanced_arrays");
     feature_flags_.angle_instanced_arrays = true;
     validators_.vertex_attribute.AddValue(GL_VERTEX_ATTRIB_ARRAY_DIVISOR_ANGLE);
   }
 
 }
 
 void FeatureInfo::AddExtensionString(const std::string& str) {
   if (extensions_.find(str) == std::string::npos) {
     extensions_ += (extensions_.empty() ? "" : " ") + str;
   }
 }
 
 }  // namespace gles2
 }  // namespace gpu