Don't set the layer property when using settings.

When using the layer settings to trace, don't also set the global
layer property.

This is something that should have been part of google#2700, but must
have been lost in one of the merges/rebases.

gapii/client/adb.go

@@ -126,23 +126,16 @@ func Start(ctx context.Context, p *android.InstalledPackage, a *android.Activity
 			return nil, cleanup.Invoke(ctx), log.Err(ctx, err, "Setting up the layer")
 		}
 		cleanup = cleanup.Then(cu)
-	}
-
-	// FileDir may fail here. This happens if/when the app is non-debuggable.
-	// Don't set up vulkan tracing here, since the loader will not try and load the layer
-	// if we aren't debuggable regardless.
-	var m *flock.Mutex
-	if o.APIs&VulkanAPI != uint32(0) {
-		m, err = reserveVulkanDevice(ctx, d)
+	} else if isVulkan {
+		m, err := reserveVulkanDevice(ctx, d)
 		if err != nil {
 			return nil, cleanup.Invoke(ctx), log.Err(ctx, err, "Setting up for tracing Vulkan")
 		}
+		cleanup = cleanup.Then(func(ctx context.Context) {
+			releaseVulkanDevice(ctx, d, m)
+		})
 	}
 
-	cleanup = cleanup.Then(func(ctx context.Context) {
-		releaseVulkanDevice(ctx, d, m)
-	})
-
 	var additionalArgs []android.ActionExtra
 	if o.AdditionalFlags != "" {
 		additionalArgs = append(additionalArgs, android.CustomExtras(text.Quote(text.SplitArgs(o.AdditionalFlags))))