diff --git a/src/backend/CommandBufferStateTracker.h b/src/backend/CommandBufferStateTracker.h
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+++ b/src/backend/CommandBufferStateTracker.h
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+// Copyright 2017 The NXT Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef BACKEND_COMMANDBUFFERSTATETRACKER_H
+#define BACKEND_COMMANDBUFFERSTATETRACKER_H
+
+#include "backend/CommandBuffer.h"
+#include "common/Constants.h"
+
+#include <bitset>
+#include <map>
+#include <set>
+
+namespace backend {
+    class CommandBufferStateTracker {
+        public:
+            explicit CommandBufferStateTracker(CommandBufferBuilder* builder);
+
+            // Non-state-modifying validation functions
+            bool HaveRenderPass() const;
+            bool ValidateCanCopy() const;
+            bool ValidateCanUseBufferAs(BufferBase* buffer, nxt::BufferUsageBit usage) const;
+            bool ValidateCanUseTextureAs(TextureBase* texture, nxt::TextureUsageBit usage) const;
+            bool ValidateCanDispatch();
+            bool ValidateCanDrawArrays();
+            bool ValidateCanDrawElements();
+            bool ValidateEndCommandBuffer() const;
+
+            // State-modifying methods
+            bool BeginSubpass();
+            bool EndSubpass();
+            bool BeginRenderPass(RenderPassBase* renderPass, FramebufferBase* framebuffer);
+            bool AdvanceSubpass();
+            bool EndRenderPass();
+            bool SetPipeline(PipelineBase* pipeline);
+            bool SetBindGroup(uint32_t index, BindGroupBase* bindgroup);
+            bool SetIndexBuffer(BufferBase* buffer);
+            bool SetVertexBuffer(uint32_t index, BufferBase* buffer);
+            bool TransitionBufferUsage(BufferBase* buffer, nxt::BufferUsageBit usage);
+            bool TransitionTextureUsage(TextureBase* texture, nxt::TextureUsageBit usage);
+
+            // These collections are copied to the CommandBuffer at build time.
+            // These pointers will remain valid since they are referenced by
+            // the bind groups which are referenced by this command buffer.
+            std::set<BufferBase*> buffersTransitioned;
+            std::set<TextureBase*> texturesTransitioned;
+
+        private:
+            enum ValidationAspect {
+                VALIDATION_ASPECT_RENDER_PIPELINE,
+                VALIDATION_ASPECT_COMPUTE_PIPELINE,
+                VALIDATION_ASPECT_BIND_GROUPS,
+                VALIDATION_ASPECT_VERTEX_BUFFERS,
+                VALIDATION_ASPECT_INDEX_BUFFER,
+
+                VALIDATION_ASPECT_COUNT
+            };
+            using ValidationAspects = std::bitset<VALIDATION_ASPECT_COUNT>;
+
+            // Usage helper functions
+            bool BufferHasGuaranteedUsageBit(BufferBase* buffer, nxt::BufferUsageBit usage) const;
+            bool TextureHasGuaranteedUsageBit(TextureBase* texture, nxt::TextureUsageBit usage) const;
+            bool IsTextureTransitionPossible(TextureBase* texture, nxt::TextureUsageBit usage) const;
+
+            // Queries for lazily evaluated aspects
+            bool RecomputeHaveAspectBindGroups();
+            bool RecomputeHaveAspectVertexBuffers();
+
+            bool HavePipeline() const;
+            bool ValidateBindGroupUsages(BindGroupBase* group) const;
+            bool RevalidateCanDraw();
+
+            void UnsetPipeline();
+
+            CommandBufferBuilder* builder;
+
+            ValidationAspects aspects;
+
+            std::bitset<kMaxBindGroups> bindgroupsSet;
+            std::bitset<kMaxVertexInputs> inputsSet;
+            PipelineBase* lastPipeline = nullptr;
+
+            std::map<BufferBase*, nxt::BufferUsageBit> mostRecentBufferUsages;
+            std::map<TextureBase*, nxt::TextureUsageBit> mostRecentTextureUsages;
+
+            RenderPassBase* currentRenderPass = nullptr;
+            FramebufferBase* currentFramebuffer = nullptr;
+            bool subpassActive = false;
+            uint32_t currentSubpass = 0;
+    };
+}
+
+#endif // BACKEND_COMMANDBUFFERSTATETRACKER_H