add missing includes for the build with use_libcxx_modules

This is to fix build error when we set use_libcxx_modules=true in
chromium build.

Bug: 40263312
Change-Id: I66dfd9310b78864f7c2109dc2bd43629e95c9665
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/221554
Commit-Queue: James Price <jrprice@google.com>
Reviewed-by: James Price <jrprice@google.com>
Auto-Submit: Takuto Ikuta <tikuta@google.com>
diff --git a/src/dawn/native/CommandAllocator.cpp b/src/dawn/native/CommandAllocator.cpp
index db4c287..d7fe14c 100644
--- a/src/dawn/native/CommandAllocator.cpp
+++ b/src/dawn/native/CommandAllocator.cpp
@@ -30,6 +30,7 @@
 #include <algorithm>
 #include <climits>
 #include <cstdlib>
+#include <new>
 #include <utility>
 
 #include "dawn/common/Assert.h"