Add basic GL functionality to the passthrough command buffer.

gpu/command_buffer/service/gl_utils.cc

 // Copyright (c) 2016 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/gl_utils.h"
 
 #include "base/metrics/histogram.h"
 #include "gpu/command_buffer/common/capabilities.h"
 #include "gpu/command_buffer/service/feature_info.h"
 #include "ui/gl/gl_version_info.h"
@@ skipping 158 matching lines @@
     caps->major_version = 3;
     caps->minor_version = 0;
   }
   if (feature_info->feature_flags().multisampled_render_to_texture ||
       feature_info->feature_flags().chromium_framebuffer_multisample ||
       feature_info->IsES3Enabled()) {
     glGetIntegerv(GL_MAX_SAMPLES, &caps->max_samples);
   }
 }
 
+bool CheckUniqueAndNonNullIds(GLsizei n, const GLuint* client_ids) {
+  if (n <= 0)
+    return true;
+  std::unordered_set<uint32_t> unique_ids(client_ids, client_ids + n);
+  return (unique_ids.size() == static_cast<size_t>(n)) &&
+         (unique_ids.find(0) == unique_ids.end());
+}
+
 }  // namespace gles2
 }  // namespace gpu