diff --git a/src/dawn_native/CommandEncoder.h b/src/dawn_native/CommandEncoder.h
index f54888f60a..6698396265 100644
--- a/src/dawn_native/CommandEncoder.h
+++ b/src/dawn_native/CommandEncoder.h
@@ -27,8 +27,6 @@
 
 namespace dawn_native {
 
-    struct BeginRenderPassCmd;
-
     using QueryAvailabilityMap = std::map<QuerySetBase*, std::vector<bool>>;
 
     class CommandEncoder final : public ObjectBase {
diff --git a/src/dawn_native/CommandValidation.h b/src/dawn_native/CommandValidation.h
index 390920341f..f0fbb105a6 100644
--- a/src/dawn_native/CommandValidation.h
+++ b/src/dawn_native/CommandValidation.h
@@ -23,9 +23,7 @@
 
 namespace dawn_native {
 
-    class AttachmentState;
     class QuerySetBase;
-    struct BeginRenderPassCmd;
     struct PassResourceUsage;
     struct TexelBlockInfo;
 
diff --git a/src/dawn_native/CreatePipelineAsyncTracker.h b/src/dawn_native/CreatePipelineAsyncTracker.h
index 73e366c089..438427adba 100644
--- a/src/dawn_native/CreatePipelineAsyncTracker.h
+++ b/src/dawn_native/CreatePipelineAsyncTracker.h
@@ -25,7 +25,6 @@ namespace dawn_native {
 
     class ComputePipelineBase;
     class DeviceBase;
-    class PipelineBase;
     class RenderPipelineBase;
 
     struct CreatePipelineAsyncTaskBase {
diff --git a/src/dawn_native/ProgrammablePassEncoder.h b/src/dawn_native/ProgrammablePassEncoder.h
index fcb74748b5..05300e7295 100644
--- a/src/dawn_native/ProgrammablePassEncoder.h
+++ b/src/dawn_native/ProgrammablePassEncoder.h
@@ -25,7 +25,6 @@
 
 namespace dawn_native {
 
-    class CommandAllocator;
     class DeviceBase;
 
     // Base class for shared functionality between ComputePassEncoder and RenderPassEncoder.
diff --git a/src/dawn_native/QueryHelper.h b/src/dawn_native/QueryHelper.h
index 4f05f09cb2..6e31bebc38 100644
--- a/src/dawn_native/QueryHelper.h
+++ b/src/dawn_native/QueryHelper.h
@@ -20,7 +20,6 @@
 namespace dawn_native {
 
     class BufferBase;
-    class DeviceBase;
     class CommandEncoder;
 
     struct TimestampParams {
diff --git a/src/dawn_native/RenderBundle.h b/src/dawn_native/RenderBundle.h
index 312954e0e0..41d686a86b 100644
--- a/src/dawn_native/RenderBundle.h
+++ b/src/dawn_native/RenderBundle.h
@@ -28,7 +28,6 @@
 
 namespace dawn_native {
 
-    struct BeginRenderPassCmd;
     struct RenderBundleDescriptor;
     class RenderBundleEncoder;
 
diff --git a/src/dawn_native/RenderPipeline.h b/src/dawn_native/RenderPipeline.h
index b6f047b364..812f7ec823 100644
--- a/src/dawn_native/RenderPipeline.h
+++ b/src/dawn_native/RenderPipeline.h
@@ -27,11 +27,7 @@
 
 namespace dawn_native {
 
-    struct BeginRenderPassCmd;
-
     class DeviceBase;
-    struct EntryPointMetadata;
-    class RenderBundleEncoder;
 
     MaybeError ValidateRenderPipelineDescriptor(DeviceBase* device,
                                                 const RenderPipelineDescriptor* descriptor);
diff --git a/src/dawn_native/d3d12/BindGroupD3D12.h b/src/dawn_native/d3d12/BindGroupD3D12.h
index 60b83683df..a48fc14225 100644
--- a/src/dawn_native/d3d12/BindGroupD3D12.h
+++ b/src/dawn_native/d3d12/BindGroupD3D12.h
@@ -25,7 +25,6 @@ namespace dawn_native { namespace d3d12 {
     class Device;
     class SamplerHeapCacheEntry;
     class ShaderVisibleDescriptorAllocator;
-    class StagingDescriptorAllocator;
 
     class BindGroup final : public BindGroupBase, public PlacementAllocated {
       public:
diff --git a/src/dawn_native/d3d12/BindGroupLayoutD3D12.h b/src/dawn_native/d3d12/BindGroupLayoutD3D12.h
index c5f32f54f3..6ee462348f 100644
--- a/src/dawn_native/d3d12/BindGroupLayoutD3D12.h
+++ b/src/dawn_native/d3d12/BindGroupLayoutD3D12.h
@@ -26,7 +26,6 @@ namespace dawn_native { namespace d3d12 {
     class BindGroup;
     class CPUDescriptorHeapAllocation;
     class Device;
-    class SamplerHeapCacheEntry;
     class StagingDescriptorAllocator;
 
     class BindGroupLayout final : public BindGroupLayoutBase {
diff --git a/src/dawn_native/d3d12/CommandBufferD3D12.cpp b/src/dawn_native/d3d12/CommandBufferD3D12.cpp
index 861d674654..4a9051d458 100644
--- a/src/dawn_native/d3d12/CommandBufferD3D12.cpp
+++ b/src/dawn_native/d3d12/CommandBufferD3D12.cpp
@@ -14,17 +14,11 @@
 
 #include "dawn_native/d3d12/CommandBufferD3D12.h"
 
-#include "common/Assert.h"
 #include "dawn_native/BindGroupTracker.h"
-#include "dawn_native/CommandEncoder.h"
 #include "dawn_native/CommandValidation.h"
-#include "dawn_native/Commands.h"
-#include "dawn_native/EnumMaskIterator.h"
 #include "dawn_native/RenderBundle.h"
 #include "dawn_native/d3d12/BindGroupD3D12.h"
 #include "dawn_native/d3d12/BindGroupLayoutD3D12.h"
-#include "dawn_native/d3d12/BufferD3D12.h"
-#include "dawn_native/d3d12/CommandRecordingContext.h"
 #include "dawn_native/d3d12/ComputePipelineD3D12.h"
 #include "dawn_native/d3d12/DeviceD3D12.h"
 #include "dawn_native/d3d12/PipelineLayoutD3D12.h"
@@ -32,16 +26,10 @@
 #include "dawn_native/d3d12/QuerySetD3D12.h"
 #include "dawn_native/d3d12/RenderPassBuilderD3D12.h"
 #include "dawn_native/d3d12/RenderPipelineD3D12.h"
-#include "dawn_native/d3d12/SamplerD3D12.h"
-#include "dawn_native/d3d12/SamplerHeapCacheD3D12.h"
 #include "dawn_native/d3d12/ShaderVisibleDescriptorAllocatorD3D12.h"
 #include "dawn_native/d3d12/StagingDescriptorAllocatorD3D12.h"
-#include "dawn_native/d3d12/TextureCopySplitter.h"
-#include "dawn_native/d3d12/TextureD3D12.h"
 #include "dawn_native/d3d12/UtilsD3D12.h"
 
-#include <deque>
-
 namespace dawn_native { namespace d3d12 {
 
     namespace {
diff --git a/src/dawn_native/d3d12/CommandBufferD3D12.h b/src/dawn_native/d3d12/CommandBufferD3D12.h
index f4d858c858..cf4c4517c2 100644
--- a/src/dawn_native/d3d12/CommandBufferD3D12.h
+++ b/src/dawn_native/d3d12/CommandBufferD3D12.h
@@ -15,12 +15,8 @@
 #ifndef DAWNNATIVE_D3D12_COMMANDBUFFERD3D12_H_
 #define DAWNNATIVE_D3D12_COMMANDBUFFERD3D12_H_
 
-#include "common/Constants.h"
 #include "dawn_native/CommandBuffer.h"
 #include "dawn_native/Error.h"
-#include "dawn_native/d3d12/Forward.h"
-
-#include <array>
 
 namespace dawn_native {
     struct BeginRenderPassCmd;
@@ -30,10 +26,7 @@ namespace dawn_native { namespace d3d12 {
 
     class BindGroupStateTracker;
     class CommandRecordingContext;
-    class Device;
-    class RenderPassDescriptorHeapTracker;
     class RenderPassBuilder;
-    class RenderPipeline;
 
     class CommandBuffer final : public CommandBufferBase {
       public:
diff --git a/src/dawn_native/d3d12/CommandRecordingContext.h b/src/dawn_native/d3d12/CommandRecordingContext.h
index d734b4433b..4fc089d424 100644
--- a/src/dawn_native/d3d12/CommandRecordingContext.h
+++ b/src/dawn_native/d3d12/CommandRecordingContext.h
@@ -15,13 +15,15 @@
 #define DAWNNATIVE_D3D12_COMMANDRECORDINGCONTEXT_H_
 
 #include "dawn_native/Error.h"
-#include "dawn_native/d3d12/TextureD3D12.h"
+#include "dawn_native/IntegerTypes.h"
 #include "dawn_native/d3d12/d3d12_platform.h"
 
 #include <set>
 
 namespace dawn_native { namespace d3d12 {
     class CommandAllocatorManager;
+    class Device;
+    class Heap;
     class Texture;
 
     class CommandRecordingContext {
diff --git a/src/dawn_native/d3d12/DeviceD3D12.cpp b/src/dawn_native/d3d12/DeviceD3D12.cpp
index d116303832..9d5041f969 100644
--- a/src/dawn_native/d3d12/DeviceD3D12.cpp
+++ b/src/dawn_native/d3d12/DeviceD3D12.cpp
@@ -14,16 +14,11 @@
 
 #include "dawn_native/d3d12/DeviceD3D12.h"
 
-#include "common/Assert.h"
-#include "dawn_native/BackendConnection.h"
-#include "dawn_native/ErrorData.h"
-#include "dawn_native/Format.h"
 #include "dawn_native/Instance.h"
 #include "dawn_native/d3d12/AdapterD3D12.h"
 #include "dawn_native/d3d12/BackendD3D12.h"
 #include "dawn_native/d3d12/BindGroupD3D12.h"
 #include "dawn_native/d3d12/BindGroupLayoutD3D12.h"
-#include "dawn_native/d3d12/BufferD3D12.h"
 #include "dawn_native/d3d12/CommandAllocatorManager.h"
 #include "dawn_native/d3d12/CommandBufferD3D12.h"
 #include "dawn_native/d3d12/ComputePipelineD3D12.h"
@@ -42,7 +37,6 @@
 #include "dawn_native/d3d12/StagingBufferD3D12.h"
 #include "dawn_native/d3d12/StagingDescriptorAllocatorD3D12.h"
 #include "dawn_native/d3d12/SwapChainD3D12.h"
-#include "dawn_native/d3d12/TextureD3D12.h"
 #include "dawn_native/d3d12/UtilsD3D12.h"
 
 #include <sstream>
diff --git a/src/dawn_native/d3d12/DeviceD3D12.h b/src/dawn_native/d3d12/DeviceD3D12.h
index c35df07f7c..113f819746 100644
--- a/src/dawn_native/d3d12/DeviceD3D12.h
+++ b/src/dawn_native/d3d12/DeviceD3D12.h
@@ -15,24 +15,16 @@
 #ifndef DAWNNATIVE_D3D12_DEVICED3D12_H_
 #define DAWNNATIVE_D3D12_DEVICED3D12_H_
 
-#include "dawn_native/dawn_platform.h"
-
-#include "common/Constants.h"
 #include "common/SerialQueue.h"
-#include "dawn_native/BindingInfo.h"
-#include "dawn_native/Commands.h"
 #include "dawn_native/Device.h"
 #include "dawn_native/d3d12/CommandRecordingContext.h"
 #include "dawn_native/d3d12/D3D12Info.h"
 #include "dawn_native/d3d12/Forward.h"
-#include "dawn_native/d3d12/ResourceHeapAllocationD3D12.h"
-
-#include <memory>
+#include "dawn_native/d3d12/TextureD3D12.h"
 
 namespace dawn_native { namespace d3d12 {
 
     class CommandAllocatorManager;
-    class DescriptorHeapAllocator;
     class PlatformFunctions;
     class ResidencyManager;
     class ResourceAllocatorManager;
diff --git a/src/dawn_native/d3d12/QueueD3D12.h b/src/dawn_native/d3d12/QueueD3D12.h
index f211d0bf58..311c607192 100644
--- a/src/dawn_native/d3d12/QueueD3D12.h
+++ b/src/dawn_native/d3d12/QueueD3D12.h
@@ -23,7 +23,6 @@
 namespace dawn_native { namespace d3d12 {
 
     class Device;
-    class CommandBuffer;
 
     class Queue final : public QueueBase {
       public:
diff --git a/src/dawn_native/d3d12/SamplerHeapCacheD3D12.h b/src/dawn_native/d3d12/SamplerHeapCacheD3D12.h
index 2e5a2d4237..3e2cf4c80b 100644
--- a/src/dawn_native/d3d12/SamplerHeapCacheD3D12.h
+++ b/src/dawn_native/d3d12/SamplerHeapCacheD3D12.h
@@ -21,7 +21,6 @@
 #include "dawn_native/d3d12/GPUDescriptorHeapAllocationD3D12.h"
 
 #include <unordered_set>
-#include <vector>
 
 // |SamplerHeapCacheEntry| maintains a cache of sampler descriptor heap allocations.
 // Each entry represents one or more sampler descriptors that co-exist in a CPU and
diff --git a/src/dawn_native/d3d12/StagingBufferD3D12.h b/src/dawn_native/d3d12/StagingBufferD3D12.h
index 291400d996..aafe60d3c8 100644
--- a/src/dawn_native/d3d12/StagingBufferD3D12.h
+++ b/src/dawn_native/d3d12/StagingBufferD3D12.h
@@ -21,7 +21,6 @@
 
 namespace dawn_native { namespace d3d12 {
 
-    class CommandRecordingContext;
     class Device;
 
     class StagingBuffer : public StagingBufferBase {
diff --git a/src/dawn_native/metal/BindGroupMTL.h b/src/dawn_native/metal/BindGroupMTL.h
index 60cbf3162d..791dbf9418 100644
--- a/src/dawn_native/metal/BindGroupMTL.h
+++ b/src/dawn_native/metal/BindGroupMTL.h
@@ -20,7 +20,6 @@
 
 namespace dawn_native { namespace metal {
 
-    class BindGroupLayout;
     class Device;
 
     class BindGroup final : public BindGroupBase, public PlacementAllocated {
diff --git a/src/dawn_native/metal/QueueMTL.h b/src/dawn_native/metal/QueueMTL.h
index 2dd718e5c0..38e79eddc4 100644
--- a/src/dawn_native/metal/QueueMTL.h
+++ b/src/dawn_native/metal/QueueMTL.h
@@ -19,7 +19,6 @@
 
 namespace dawn_native { namespace metal {
 
-    class CommandBuffer;
     class Device;
 
     class Queue final : public QueueBase {
diff --git a/src/dawn_native/opengl/BindGroupGL.h b/src/dawn_native/opengl/BindGroupGL.h
index f9f1151410..5544a492dd 100644
--- a/src/dawn_native/opengl/BindGroupGL.h
+++ b/src/dawn_native/opengl/BindGroupGL.h
@@ -20,7 +20,6 @@
 
 namespace dawn_native { namespace opengl {
 
-    class BindGroupLayout;
     class Device;
 
     MaybeError ValidateGLBindGroupDescriptor(const BindGroupDescriptor* descriptor);
diff --git a/src/dawn_native/opengl/CommandBufferGL.h b/src/dawn_native/opengl/CommandBufferGL.h
index 8f300be9e2..c21f574668 100644
--- a/src/dawn_native/opengl/CommandBufferGL.h
+++ b/src/dawn_native/opengl/CommandBufferGL.h
@@ -24,7 +24,6 @@ namespace dawn_native {
 namespace dawn_native { namespace opengl {
 
     class Device;
-    struct OpenGLFunctions;
 
     class CommandBuffer final : public CommandBufferBase {
       public:
diff --git a/src/dawn_native/opengl/PipelineGL.h b/src/dawn_native/opengl/PipelineGL.h
index 1d995d0e8a..33e53410de 100644
--- a/src/dawn_native/opengl/PipelineGL.h
+++ b/src/dawn_native/opengl/PipelineGL.h
@@ -29,7 +29,6 @@ namespace dawn_native {
 namespace dawn_native { namespace opengl {
 
     struct OpenGLFunctions;
-    class PersistentPipelineState;
     class PipelineLayout;
     class Sampler;
 
diff --git a/src/dawn_native/opengl/QueueGL.h b/src/dawn_native/opengl/QueueGL.h
index d34ee16846..a95e1a4ea6 100644
--- a/src/dawn_native/opengl/QueueGL.h
+++ b/src/dawn_native/opengl/QueueGL.h
@@ -19,7 +19,6 @@
 
 namespace dawn_native { namespace opengl {
 
-    class CommandBuffer;
     class Device;
 
     class Queue final : public QueueBase {
diff --git a/src/dawn_native/vulkan/CommandRecordingContext.h b/src/dawn_native/vulkan/CommandRecordingContext.h
index 2749fd2841..a8dd68d2e7 100644
--- a/src/dawn_native/vulkan/CommandRecordingContext.h
+++ b/src/dawn_native/vulkan/CommandRecordingContext.h
@@ -18,11 +18,7 @@
 
 #include "dawn_native/vulkan/BufferVk.h"
 
-#include <vector>
-
 namespace dawn_native { namespace vulkan {
-    class Buffer;
-
     // Used to track operations that are handled after recording.
     // Currently only tracks semaphores, but may be used to do barrier coalescing in the future.
     struct CommandRecordingContext {
diff --git a/src/dawn_native/vulkan/QueueVk.h b/src/dawn_native/vulkan/QueueVk.h
index d5d15af5c5..b3aa66538e 100644
--- a/src/dawn_native/vulkan/QueueVk.h
+++ b/src/dawn_native/vulkan/QueueVk.h
@@ -19,7 +19,6 @@
 
 namespace dawn_native { namespace vulkan {
 
-    class CommandBuffer;
     class Device;
 
     class Queue final : public QueueBase {