Remove some unnecessary #include

Change-Id: I51382e4b4d68da55631d37b1b72fecaaef2b16ee
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/124020
Reviewed-by: Austin Eng <enga@chromium.org>
Commit-Queue: Peng Huang <penghuang@chromium.org>
Kokoro: Kokoro <noreply+kokoro@google.com>
diff --git a/src/dawn/native/d3d/PlatformFunctions.cpp b/src/dawn/native/d3d/PlatformFunctions.cpp
index 52bfa0d..4295fdb 100644
--- a/src/dawn/native/d3d/PlatformFunctions.cpp
+++ b/src/dawn/native/d3d/PlatformFunctions.cpp
@@ -21,8 +21,6 @@
 #include <sstream>
 #include <utility>
 
-#include "dawn/common/DynamicLib.h"
-
 namespace dawn::native::d3d {
 namespace {
 // Extract Version from "10.0.{Version}.0" if possible, otherwise return 0.
diff --git a/src/dawn/native/d3d/PlatformFunctions.h b/src/dawn/native/d3d/PlatformFunctions.h
index 59fe910..f039078 100644
--- a/src/dawn/native/d3d/PlatformFunctions.h
+++ b/src/dawn/native/d3d/PlatformFunctions.h
@@ -19,10 +19,9 @@
 
 #include <string>
 
-#include "dawn/native/d3d/d3d_platform.h"
-
 #include "dawn/common/DynamicLib.h"
 #include "dawn/native/Error.h"
+#include "dawn/native/d3d/d3d_platform.h"
 
 namespace dawn::native::d3d {
 
diff --git a/src/dawn/native/d3d12/PlatformFunctionsD3D12.cpp b/src/dawn/native/d3d12/PlatformFunctionsD3D12.cpp
index a249997..2cd1c40 100644
--- a/src/dawn/native/d3d12/PlatformFunctionsD3D12.cpp
+++ b/src/dawn/native/d3d12/PlatformFunctionsD3D12.cpp
@@ -14,14 +14,7 @@
 
 #include "dawn/native/d3d12/PlatformFunctionsD3D12.h"
 
-#include <comdef.h>
-
-#include <algorithm>
-#include <array>
-#include <sstream>
-#include <utility>
-
-#include "dawn/common/DynamicLib.h"
+#include <string>
 
 namespace dawn::native::d3d12 {
 
diff --git a/src/dawn/native/d3d12/PlatformFunctionsD3D12.h b/src/dawn/native/d3d12/PlatformFunctionsD3D12.h
index af6ae35..22c59d8 100644
--- a/src/dawn/native/d3d12/PlatformFunctionsD3D12.h
+++ b/src/dawn/native/d3d12/PlatformFunctionsD3D12.h
@@ -15,22 +15,14 @@
 #ifndef SRC_DAWN_NATIVE_D3D12_PLATFORMFUNCTIONS_H_
 #define SRC_DAWN_NATIVE_D3D12_PLATFORMFUNCTIONS_H_
 
-#include <d3dcompiler.h>
-
-#include <string>
-
 #include "dawn/native/d3d/PlatformFunctions.h"
 #include "dawn/native/d3d12/d3d12_platform.h"
 
 #include "dawn/common/DynamicLib.h"
-#include "dawn/native/Error.h"
 
 namespace dawn::native::d3d12 {
 
-// Loads the functions required from the platform dynamically so that we don't need to rely on
-// them being present in the system. For example linking against d3d12.lib would prevent
-// dawn_native from loading on Windows 7 system where d3d12.dll doesn't exist.
-class PlatformFunctions : public d3d::PlatformFunctions {
+class PlatformFunctions final : public d3d::PlatformFunctions {
   public:
     PlatformFunctions();
     ~PlatformFunctions() override;