Bug 1992430 - Disable WebGPU if the GPU process is disabled on platforms with a GPU process. r=webgpu-reviewers,jimb

Differential Revision: https://phabricator.services.mozilla.com/D267425

Author: aosmond

gfx/thebes/gfxPlatform.cpp

@@ -3252,6 +3252,13 @@ void gfxPlatform::InitWebGPUConfig() {
   FeatureState& featureWebGPU = gfxConfig::GetFeature(Feature::WEBGPU);
   featureWebGPU.EnableByDefault();
 
+  if (!gfxConfig::IsEnabled(Feature::GPU_PROCESS) &&
+      !StaticPrefs::dom_webgpu_allow_in_parent_AtStartup()) {
+    featureWebGPU.Disable(FeatureStatus::UnavailableNoGpuProcess,
+                          "Disabled without GPU process",
+                          "FEATURE_WEBGPU_NO_GPU_PROCESS"_ns);
+  }
+
   nsCString message;
   nsCString failureId;
   if (!IsGfxInfoStatusOkay(nsIGfxInfo::FEATURE_WEBGPU, &message, failureId)) {
@@ -4024,6 +4031,14 @@ bool gfxPlatform::FallbackFromAcceleration(FeatureStatus aStatus,
 
 /* static */
 void gfxPlatform::DisableGPUProcess() {
+  if (gfxVars::AllowWebGPU() &&
+      !StaticPrefs::dom_webgpu_allow_in_parent_AtStartup()) {
+    gfxConfig::Disable(Feature::WEBGPU, FeatureStatus::UnavailableNoGpuProcess,
+                       "Disabled by GPU process disabled",
+                       "FEATURE_WEBGPU_DISABLED_BY_GPU_PROCESS_DISABLED"_ns);
+    gfxVars::SetAllowWebGPU(false);
+  }
+
   if (gfxVars::RemoteCanvasEnabled() &&
       !StaticPrefs::gfx_canvas_remote_allow_in_parent_AtStartup()) {
     gfxConfig::Disable(

modules/libpref/init/StaticPrefList.yaml

@@ -5547,6 +5547,17 @@
 #endif
   mirror: always
 
+# Is WebGPU allowed to run in the parent process? This should be false if
+# on a platform that supports the GPU process, else true.
+- name: dom.webgpu.allow-in-parent
+  type: bool
+#if defined(XP_WIN) || defined(ANDROID)
+  value: false
+#else
+  value: true
+#endif
+  mirror: once
+
 # Is support for the Web GPU API enabled on service workers?
 - name: dom.webgpu.service-workers.enabled
   type: RelaxedAtomicBool