Remove robustness gate for vertex pulling.

We want to always default vertex pulling to true, regardless of the
state of robustness. Remove the guard on setting the default to true.

Change-Id: I7ec24bec5217253669dfb9a3c8032821f4ba33d9
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/272894
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Commit-Queue: dan sinclair <dsinclair@chromium.org>

Author: dj2

src/dawn/native/metal/PhysicalDeviceMTL.mm

@@ -423,11 +423,9 @@ bool IsGPUCounterSupported(id<MTLDevice> device,
         deviceToggles->Default(Toggle::DisableBaseInstance, !haveBaseVertexBaseInstance);
     }
 
-    // Vertex buffer robustness is implemented by using programmable vertex pulling. Enable
-    // that code path if it isn't explicitly disabled.
-    if (!deviceToggles->IsEnabled(Toggle::DisableRobustness)) {
-        deviceToggles->Default(Toggle::MetalEnableVertexPulling, true);
-    }
+    // Vertex buffer robustness is implemented by using programmable vertex pulling. The
+    // VertexPulling transform also handles non-4-byte aligned vertex buffer accesses.
+    deviceToggles->Default(Toggle::MetalEnableVertexPulling, true);
 
     // Shader `discard_fragment` changed semantics to be uniform in Metal 2.3+. See section 6.10.1.3
     // of the Metal Spec (v3.2).