Implement SamplerManager in the command buffer

gpu/command_buffer/service/context_state.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/context_state.h"
 
 #include <cmath>
 
 #include "gpu/command_buffer/common/gles2_cmd_utils.h"
 #include "gpu/command_buffer/service/buffer_manager.h"
@@ skipping 567 matching lines @@
       }
       glBindTexture(GL_TEXTURE_2D_ARRAY, 0);
     }
   }
 
   if (active_unit != active_texture_unit) {
     glActiveTexture(GL_TEXTURE0 + active_texture_unit);
   }
 }
 
+void ContextState::UnbindSampler(Sampler* sampler) {
+  for (size_t jj = 0; jj < sampler_units.size(); ++jj) {
+    if (sampler_units[jj].get() == sampler) {
+      sampler_units[jj] = nullptr;
+      glBindSampler(jj, 0);
+    }
+  }
+}
+
 // Include the auto-generated part of this file. We split this because it means
 // we can easily edit the non-auto generated parts right here in this file
 // instead of having to edit some template or the code generator.
 #include "gpu/command_buffer/service/context_state_impl_autogen.h"
 
 }  // namespace gles2
 }  // namespace gpu