Revert "Reland "[webgpu-headers] Removes define for signalValue.""

This reverts commit ff76ecc5af96e5d307e4fcd3642401376423806a.

Reason for revert: Breaking in chromium Blink side.

Original change's description:
> Reland "[webgpu-headers] Removes define for signalValue."
>
> This is a reland of commit 79cd63939a7cb9d56cd5ebfc2af6d7e225cd102d
>
> Original change's description:
> > [webgpu-headers] Removes define for signalValue.
> >
> > See issue: github.com/webgpu-native/webgpu-headers/issues/130
> >
> > Change-Id: I8e37e489f864fe72a822d9ad0c3d42c780023997
> > Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/155980
> > Kokoro: Kokoro <noreply+kokoro@google.com>
> > Commit-Queue: Loko Kung <lokokung@google.com>
> > Reviewed-by: Austin Eng <enga@chromium.org>
>
> Change-Id: I8e70d9d04079f60aeec72d4a62d08b34a8d6e2df
> Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/155991
> Kokoro: Kokoro <noreply+kokoro@google.com>
> Reviewed-by: Corentin Wallez <cwallez@chromium.org>
> Commit-Queue: Loko Kung <lokokung@google.com>
> Reviewed-by: Austin Eng <enga@chromium.org>

TBR=cwallez@chromium.org,enga@chromium.org,noreply+kokoro@google.com,dawn-scoped@luci-project-accounts.iam.gserviceaccount.com,lokokung@google.com

Change-Id: Idc31270d340e3921308c2a9837ead2006ed5a949
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/156480
Kokoro: Loko Kung <lokokung@google.com>
Commit-Queue: Loko Kung <lokokung@google.com>
Reviewed-by: Loko Kung <lokokung@google.com>
Reviewed-by: Austin Eng <enga@chromium.org>
diff --git a/generator/templates/api.h b/generator/templates/api.h
index 894df1f..0232d46 100644
--- a/generator/templates/api.h
+++ b/generator/templates/api.h
@@ -67,6 +67,8 @@
 #define {{API}}_NULLABLE
 #endif
 
+#define WGPU_BREAKING_WORK_DONE_SIGNAL_VALUE_CHANGE
+
 #include <stdint.h>
 #include <stddef.h>