Force time elapsed queries on certain drivers.

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 636 matching lines @@
     validators_.texture_internal_format.AddValue(GL_BGRA_EXT);
     validators_.texture_format.AddValue(GL_BGRA_EXT);
     validators_.texture_unsized_internal_format.AddValue(GL_BGRA_EXT);
   }
 
   if (enable_read_format_bgra) {
     AddExtensionString("GL_EXT_read_format_bgra");
     validators_.read_pixel_format.AddValue(GL_BGRA_EXT);
   }
 
-  // We only support timer queries if we also support glGetInteger64v.
-  // For GL_EXT_disjoint_timer_query, glGetInteger64v is only support under ES3.
-  if ((gl_version_info_->is_es3 &&
-       extensions.Contains("GL_EXT_disjoint_timer_query")) ||
+  // glGetInteger64v for timestamps is implemented on the client side in a way
+  // that it does not depend on a driver-level implementation of
+  // glGetInteger64v. The GPUTimer class which implements timer queries can also
+  // fallback to an implementation that does not depend on glGetInteget64v on
+  // ES2. Thus we can enable GL_EXT_disjoint_timer_query on ES2 contexts even
+  // though it does not support glGetInteger64v due to a specification bug.
+  if (extensions.Contains("GL_EXT_disjoint_timer_query") ||
       extensions.Contains("GL_ARB_timer_query") ||
       extensions.Contains("GL_EXT_timer_query")) {
     AddExtensionString("GL_EXT_disjoint_timer_query");
   }
 
   if (enable_render_buffer_bgra) {
     feature_flags_.ext_render_buffer_format_bgra8888 = true;
     AddExtensionString("GL_CHROMIUM_renderbuffer_format_BGRA8888");
     validators_.render_buffer_format.AddValue(GL_BGRA8_EXT);
   }
@@ skipping 764 matching lines @@
   if (pos == std::string::npos) {
     extensions_ += (extensions_.empty() ? "" : " ") + str;
   }
 }
 
 FeatureInfo::~FeatureInfo() {
 }
 
 }  // namespace gles2
 }  // namespace gpu