Add external_texture test. (#3544)

This CL adds a test which creates a pipeline with an external_texture.
It doesn't attempt to use the texture, just creates the pipeline to
validate there are no errors on creation.

src/webgpu/api/validation/render_pipeline/misc.spec.ts

@@ -96,3 +96,37 @@ g.test('pipeline_layout,device_mismatch')
 
     t.doCreateRenderPipelineTest(isAsync, !mismatched, descriptor);
   });
+
+g.test('external_texture')
+  .desc('Tests createRenderPipeline() with an external_texture')
+  .fn(t => {
+    const shader = t.device.createShaderModule({
+      code: `
+        @vertex
+        fn vertexMain() -> @builtin(position) vec4f {
+          return vec4f(1);
+        }
+
+        @group(0) @binding(0) var myTexture: texture_external;
+
+        @fragment
+        fn fragmentMain() -> @location(0) vec4f {
+          let result = textureLoad(myTexture, vec2u(1, 1));
+          return vec4f(1);
+        }
+      `,
+    });
+
+    const descriptor: GPURenderPipelineDescriptor = {
+      layout: 'auto',
+      vertex: {
+        module: shader,
+      },
+      fragment: {
+        module: shader,
+        targets: [{ format: 'rgba8unorm' }],
+      },
+    };
+
+    t.doCreateRenderPipelineTest(false, true, descriptor);
+  });

src/webgpu/listing_meta.json

@@ -730,6 +730,7 @@
   "webgpu:api,validation,render_pipeline,inter_stage:max_shader_variable_location:*": { "subcaseMS": 11.050 },
   "webgpu:api,validation,render_pipeline,inter_stage:type:*": { "subcaseMS": 6.170 },
   "webgpu:api,validation,render_pipeline,misc:basic:*": { "subcaseMS": 0.901 },
+  "webgpu:api,validation,render_pipeline,misc:external_texture:*": { "subcaseMS": 35.189 },
   "webgpu:api,validation,render_pipeline,misc:pipeline_layout,device_mismatch:*": { "subcaseMS": 8.700 },
   "webgpu:api,validation,render_pipeline,misc:vertex_state_only:*": { "subcaseMS": 1.125 },
   "webgpu:api,validation,render_pipeline,multisample_state:alpha_to_coverage,count:*": { "subcaseMS": 3.200 },