Make dawn_native link against user32.lib on Windows

This is required for the call to the IsWindow function that's in
Surface.cpp.

Bug: chromium:1064305
Change-Id: I0c4a6ed17ba4aada994262d393de142de3f26144
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/19282
Reviewed-by: Austin Eng <enga@chromium.org>
Commit-Queue: Corentin Wallez <cwallez@chromium.org>

src/dawn_native/BUILD.gn

@@ -262,6 +262,14 @@ source_set("dawn_native_sources") {
     "dawn_platform.h",
   ]
 
+  if (dawn_use_x11) {
+    libs += [ "X11" ]
+  }
+
+  if (is_win) {
+    libs += [ "user32.lib" ]
+  }
+
   if (dawn_enable_d3d12) {
     libs += [ "dxguid.lib" ]
     sources += [
@@ -558,10 +566,6 @@ source_set("dawn_native_sources") {
       ]
     }
   }
-
-  if (dawn_use_x11) {
-    libs += [ "X11" ]
-  }
 }
 
 # The static and shared libraries for dawn_native. Most of the files are

src/dawn_native/CMakeLists.txt

@@ -151,6 +151,10 @@ if (DAWN_USE_X11)
     target_link_libraries(dawn_native PRIVATE ${X11_LIBRARIES})
 endif()
 
+if (WIN32)
+    target_link_libraries(dawn_native PRIVATE user32.lib)
+endif()
+
 if (DAWN_ENABLE_D3D12)
     target_sources(dawn_native PRIVATE
         "${DAWN_INCLUDE_DIR}/dawn_native/D3D12Backend.h"