diff --git a/src/backend/CMakeLists.txt b/src/backend/CMakeLists.txt
index a93acbbab5..4436f635d6 100644
--- a/src/backend/CMakeLists.txt
+++ b/src/backend/CMakeLists.txt
@@ -66,10 +66,11 @@ if (NXT_ENABLE_OPENGL)
         ${OPENGL_DIR}/ComputePipelineGL.h
         ${OPENGL_DIR}/DepthStencilStateGL.cpp
         ${OPENGL_DIR}/DepthStencilStateGL.h
+        ${OPENGL_DIR}/DeviceGL.cpp
+        ${OPENGL_DIR}/DeviceGL.h
+        ${OPENGL_DIR}/Forward.h
         ${OPENGL_DIR}/InputStateGL.cpp
         ${OPENGL_DIR}/InputStateGL.h
-        ${OPENGL_DIR}/OpenGLBackend.cpp
-        ${OPENGL_DIR}/OpenGLBackend.h
         ${OPENGL_DIR}/PersistentPipelineStateGL.cpp
         ${OPENGL_DIR}/PersistentPipelineStateGL.h
         ${OPENGL_DIR}/PipelineGL.cpp
diff --git a/src/backend/opengl/BlendStateGL.cpp b/src/backend/opengl/BlendStateGL.cpp
index 42d981e905..1f49138bda 100644
--- a/src/backend/opengl/BlendStateGL.cpp
+++ b/src/backend/opengl/BlendStateGL.cpp
@@ -14,7 +14,6 @@
 
 #include "backend/opengl/BlendStateGL.h"
 
-#include "backend/opengl/OpenGLBackend.h"
 #include "common/Assert.h"
 
 namespace backend { namespace opengl {
diff --git a/src/backend/opengl/BufferGL.cpp b/src/backend/opengl/BufferGL.cpp
index 6fa5a95a01..e282975c6b 100644
--- a/src/backend/opengl/BufferGL.cpp
+++ b/src/backend/opengl/BufferGL.cpp
@@ -14,8 +14,6 @@
 
 #include "backend/opengl/BufferGL.h"
 
-#include "backend/opengl/OpenGLBackend.h"
-
 namespace backend { namespace opengl {
 
     // Buffer
diff --git a/src/backend/opengl/CommandBufferGL.cpp b/src/backend/opengl/CommandBufferGL.cpp
index 5343f40d80..b5a1540636 100644
--- a/src/backend/opengl/CommandBufferGL.cpp
+++ b/src/backend/opengl/CommandBufferGL.cpp
@@ -14,11 +14,12 @@
 
 #include "backend/opengl/CommandBufferGL.h"
 
+#include "backend/BindGroup.h"
 #include "backend/Commands.h"
 #include "backend/opengl/BufferGL.h"
 #include "backend/opengl/ComputePipelineGL.h"
+#include "backend/opengl/Forward.h"
 #include "backend/opengl/InputStateGL.h"
-#include "backend/opengl/OpenGLBackend.h"
 #include "backend/opengl/PersistentPipelineStateGL.h"
 #include "backend/opengl/PipelineLayoutGL.h"
 #include "backend/opengl/RenderPipelineGL.h"
diff --git a/src/backend/opengl/DepthStencilStateGL.cpp b/src/backend/opengl/DepthStencilStateGL.cpp
index 0df1cf08f0..97a7f1588f 100644
--- a/src/backend/opengl/DepthStencilStateGL.cpp
+++ b/src/backend/opengl/DepthStencilStateGL.cpp
@@ -14,7 +14,6 @@
 
 #include "backend/opengl/DepthStencilStateGL.h"
 
-#include "backend/opengl/OpenGLBackend.h"
 #include "backend/opengl/PersistentPipelineStateGL.h"
 #include "common/Assert.h"
 
diff --git a/src/backend/opengl/OpenGLBackend.cpp b/src/backend/opengl/DeviceGL.cpp
similarity index 90%
rename from src/backend/opengl/OpenGLBackend.cpp
rename to src/backend/opengl/DeviceGL.cpp
index 6aec34db1e..1b77e9b127 100644
--- a/src/backend/opengl/OpenGLBackend.cpp
+++ b/src/backend/opengl/DeviceGL.cpp
@@ -12,8 +12,11 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-#include "backend/opengl/OpenGLBackend.h"
+#include "backend/opengl/DeviceGL.h"
 
+#include "backend/BindGroup.h"
+#include "backend/BindGroupLayout.h"
+#include "backend/RenderPassDescriptor.h"
 #include "backend/opengl/BlendStateGL.h"
 #include "backend/opengl/BufferGL.h"
 #include "backend/opengl/CommandBufferGL.h"
@@ -106,17 +109,6 @@ namespace backend { namespace opengl {
     void Device::TickImpl() {
     }
 
-    // Bind Group
-
-    BindGroup::BindGroup(BindGroupBuilder* builder) : BindGroupBase(builder) {
-    }
-
-    // Bind Group Layout
-
-    BindGroupLayout::BindGroupLayout(BindGroupLayoutBuilder* builder)
-        : BindGroupLayoutBase(builder) {
-    }
-
     // Queue
 
     Queue::Queue(Device* device) : QueueBase(device) {
@@ -128,10 +120,4 @@ namespace backend { namespace opengl {
         }
     }
 
-    // RenderPassDescriptor
-
-    RenderPassDescriptor::RenderPassDescriptor(RenderPassDescriptorBuilder* builder)
-        : RenderPassDescriptorBase(builder) {
-    }
-
 }}  // namespace backend::opengl
diff --git a/src/backend/opengl/OpenGLBackend.h b/src/backend/opengl/DeviceGL.h
similarity index 51%
rename from src/backend/opengl/OpenGLBackend.h
rename to src/backend/opengl/DeviceGL.h
index a6dc1b7f4e..4fdcea1994 100644
--- a/src/backend/opengl/OpenGLBackend.h
+++ b/src/backend/opengl/DeviceGL.h
@@ -1,4 +1,4 @@
-// Copyright 2017 The NXT Authors
+// Copyright 2018 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.
@@ -12,75 +12,19 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-#ifndef BACKEND_OPENGL_OPENGLBACKEND_H_
-#define BACKEND_OPENGL_OPENGLBACKEND_H_
+#ifndef BACKEND_OPENGL_DEVICEGL_H_
+#define BACKEND_OPENGL_DEVICEGL_H_
 
 #include "nxt/nxtcpp.h"
 
-#include "backend/BindGroup.h"
-#include "backend/BindGroupLayout.h"
-#include "backend/BlendState.h"
-#include "backend/Buffer.h"
-#include "backend/DepthStencilState.h"
 #include "backend/Device.h"
-#include "backend/InputState.h"
 #include "backend/Queue.h"
-#include "backend/RenderPassDescriptor.h"
-#include "backend/ToBackend.h"
+#include "backend/opengl/Forward.h"
 
 #include "glad/glad.h"
 
 namespace backend { namespace opengl {
 
-    class BindGroup;
-    class BindGroupLayout;
-    class BlendState;
-    class Buffer;
-    class BufferView;
-    class CommandBuffer;
-    class ComputePipeline;
-    class DepthStencilState;
-    class Device;
-    class InputState;
-    class PersistentPipelineState;
-    class PipelineLayout;
-    class Queue;
-    class RenderPassDescriptor;
-    class RenderPipeline;
-    class Sampler;
-    class ShaderModule;
-    class SwapChain;
-    class Texture;
-    class TextureView;
-
-    struct OpenGLBackendTraits {
-        using BindGroupType = BindGroup;
-        using BindGroupLayoutType = BindGroupLayout;
-        using BlendStateType = BlendState;
-        using BufferType = Buffer;
-        using BufferViewType = BufferView;
-        using CommandBufferType = CommandBuffer;
-        using ComputePipelineType = ComputePipeline;
-        using DepthStencilStateType = DepthStencilState;
-        using DeviceType = Device;
-        using InputStateType = InputState;
-        using PipelineLayoutType = PipelineLayout;
-        using QueueType = Queue;
-        using RenderPassDescriptorType = RenderPassDescriptor;
-        using RenderPipelineType = RenderPipeline;
-        using SamplerType = Sampler;
-        using ShaderModuleType = ShaderModule;
-        using SwapChainType = SwapChain;
-        using TextureType = Texture;
-        using TextureViewType = TextureView;
-    };
-
-    template <typename T>
-    auto ToBackend(T&& common) -> decltype(ToBackendBase<OpenGLBackendTraits>(common)) {
-        return ToBackendBase<OpenGLBackendTraits>(common);
-    }
-
-    // Definition of backend types
     class Device : public DeviceBase {
       public:
         BindGroupBase* CreateBindGroup(BindGroupBuilder* builder) override;
@@ -109,16 +53,6 @@ namespace backend { namespace opengl {
             const nxt::SamplerDescriptor* descriptor) override;
     };
 
-    class BindGroup : public BindGroupBase {
-      public:
-        BindGroup(BindGroupBuilder* builder);
-    };
-
-    class BindGroupLayout : public BindGroupLayoutBase {
-      public:
-        BindGroupLayout(BindGroupLayoutBuilder* builder);
-    };
-
     class Queue : public QueueBase {
       public:
         Queue(Device* device);
@@ -127,11 +61,6 @@ namespace backend { namespace opengl {
         void Submit(uint32_t numCommands, CommandBuffer* const* commands);
     };
 
-    class RenderPassDescriptor : public RenderPassDescriptorBase {
-      public:
-        RenderPassDescriptor(RenderPassDescriptorBuilder* builder);
-    };
-
 }}  // namespace backend::opengl
 
-#endif  // BACKEND_OPENGL_OPENGLBACKEND_H_
+#endif  // BACKEND_OPENGL_DEVICEGL_H_
diff --git a/src/backend/opengl/Forward.h b/src/backend/opengl/Forward.h
new file mode 100644
index 0000000000..79a00cf795
--- /dev/null
+++ b/src/backend/opengl/Forward.h
@@ -0,0 +1,78 @@
+// Copyright 2018 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_OPENGL_FORWARD_H_
+#define BACKEND_OPENGL_FORWARD_H_
+
+#include "backend/ToBackend.h"
+
+namespace {
+    class BindGroupBase;
+    class BindGroup;
+    class RenderPassDescriptor;
+}  // namespace
+
+namespace backend { namespace opengl {
+
+    using BindGroup = BindGroupBase;
+    using BindGroupLayout = BindGroupLayoutBase;
+    class BlendState;
+    class Buffer;
+    class BufferView;
+    class CommandBuffer;
+    class ComputePipeline;
+    class DepthStencilState;
+    class Device;
+    class InputState;
+    class PersistentPipelineState;
+    class PipelineLayout;
+    class Queue;
+    using RenderPassDescriptor = RenderPassDescriptorBase;
+    class RenderPipeline;
+    class Sampler;
+    class ShaderModule;
+    class SwapChain;
+    class Texture;
+    class TextureView;
+
+    struct OpenGLBackendTraits {
+        using BindGroupType = BindGroup;
+        using BindGroupLayoutType = BindGroupLayout;
+        using BlendStateType = BlendState;
+        using BufferType = Buffer;
+        using BufferViewType = BufferView;
+        using CommandBufferType = CommandBuffer;
+        using ComputePipelineType = ComputePipeline;
+        using DepthStencilStateType = DepthStencilState;
+        using DeviceType = Device;
+        using InputStateType = InputState;
+        using PipelineLayoutType = PipelineLayout;
+        using QueueType = Queue;
+        using RenderPassDescriptorType = RenderPassDescriptor;
+        using RenderPipelineType = RenderPipeline;
+        using SamplerType = Sampler;
+        using ShaderModuleType = ShaderModule;
+        using SwapChainType = SwapChain;
+        using TextureType = Texture;
+        using TextureViewType = TextureView;
+    };
+
+    template <typename T>
+    auto ToBackend(T&& common) -> decltype(ToBackendBase<OpenGLBackendTraits>(common)) {
+        return ToBackendBase<OpenGLBackendTraits>(common);
+    }
+
+}}  // namespace backend::opengl
+
+#endif  // BACKEND_OPENGL_FORWARD_H_
diff --git a/src/backend/opengl/GeneratedCodeIncludes.h b/src/backend/opengl/GeneratedCodeIncludes.h
index b47f055eaa..33b38d10f8 100644
--- a/src/backend/opengl/GeneratedCodeIncludes.h
+++ b/src/backend/opengl/GeneratedCodeIncludes.h
@@ -12,13 +12,16 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+#include "backend/BindGroup.h"
+#include "backend/BindGroupLayout.h"
+#include "backend/RenderPassDescriptor.h"
 #include "backend/opengl/BlendStateGL.h"
 #include "backend/opengl/BufferGL.h"
 #include "backend/opengl/CommandBufferGL.h"
 #include "backend/opengl/ComputePipelineGL.h"
 #include "backend/opengl/DepthStencilStateGL.h"
+#include "backend/opengl/DeviceGL.h"
 #include "backend/opengl/InputStateGL.h"
-#include "backend/opengl/OpenGLBackend.h"
 #include "backend/opengl/PersistentPipelineStateGL.h"
 #include "backend/opengl/PipelineLayoutGL.h"
 #include "backend/opengl/RenderPipelineGL.h"
diff --git a/src/backend/opengl/InputStateGL.cpp b/src/backend/opengl/InputStateGL.cpp
index 8bb04e532e..7f20bfb361 100644
--- a/src/backend/opengl/InputStateGL.cpp
+++ b/src/backend/opengl/InputStateGL.cpp
@@ -14,7 +14,6 @@
 
 #include "backend/opengl/InputStateGL.h"
 
-#include "backend/opengl/OpenGLBackend.h"
 #include "common/Assert.h"
 
 namespace backend { namespace opengl {
diff --git a/src/backend/opengl/PersistentPipelineStateGL.cpp b/src/backend/opengl/PersistentPipelineStateGL.cpp
index 7f0f54cade..0f88c74378 100644
--- a/src/backend/opengl/PersistentPipelineStateGL.cpp
+++ b/src/backend/opengl/PersistentPipelineStateGL.cpp
@@ -14,8 +14,6 @@
 
 #include "backend/opengl/PersistentPipelineStateGL.h"
 
-#include "backend/opengl/OpenGLBackend.h"
-
 namespace backend { namespace opengl {
 
     void PersistentPipelineState::SetDefaultState() {
diff --git a/src/backend/opengl/PipelineGL.cpp b/src/backend/opengl/PipelineGL.cpp
index b33875e1b9..a71702b7dd 100644
--- a/src/backend/opengl/PipelineGL.cpp
+++ b/src/backend/opengl/PipelineGL.cpp
@@ -14,7 +14,8 @@
 
 #include "backend/opengl/PipelineGL.h"
 
-#include "backend/opengl/OpenGLBackend.h"
+#include "backend/BindGroupLayout.h"
+#include "backend/opengl/Forward.h"
 #include "backend/opengl/PersistentPipelineStateGL.h"
 #include "backend/opengl/PipelineLayoutGL.h"
 #include "backend/opengl/ShaderModuleGL.h"
diff --git a/src/backend/opengl/PipelineLayoutGL.cpp b/src/backend/opengl/PipelineLayoutGL.cpp
index c9c0b563ab..444246df80 100644
--- a/src/backend/opengl/PipelineLayoutGL.cpp
+++ b/src/backend/opengl/PipelineLayoutGL.cpp
@@ -14,7 +14,7 @@
 
 #include "backend/opengl/PipelineLayoutGL.h"
 
-#include "backend/opengl/OpenGLBackend.h"
+#include "backend/BindGroupLayout.h"
 
 namespace backend { namespace opengl {
 
diff --git a/src/backend/opengl/RenderPipelineGL.cpp b/src/backend/opengl/RenderPipelineGL.cpp
index 96a5b3c343..057d09d1ab 100644
--- a/src/backend/opengl/RenderPipelineGL.cpp
+++ b/src/backend/opengl/RenderPipelineGL.cpp
@@ -16,8 +16,8 @@
 
 #include "backend/opengl/BlendStateGL.h"
 #include "backend/opengl/DepthStencilStateGL.h"
+#include "backend/opengl/Forward.h"
 #include "backend/opengl/InputStateGL.h"
-#include "backend/opengl/OpenGLBackend.h"
 #include "backend/opengl/PersistentPipelineStateGL.h"
 
 namespace backend { namespace opengl {
diff --git a/src/backend/opengl/SamplerGL.cpp b/src/backend/opengl/SamplerGL.cpp
index db2eb530b3..3ad06aa9b1 100644
--- a/src/backend/opengl/SamplerGL.cpp
+++ b/src/backend/opengl/SamplerGL.cpp
@@ -14,7 +14,7 @@
 
 #include "backend/opengl/SamplerGL.h"
 
-#include "backend/opengl/OpenGLBackend.h"
+#include "backend/opengl/DeviceGL.h"
 #include "common/Assert.h"
 
 namespace backend { namespace opengl {