tint/ast: Remove ast::Sampler

Instead use ast::TypeName.

Bug: tint:1810
Change-Id: Ia2641d661cab70d110c975d5f0d0e76628816cb0
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/119120
Reviewed-by: Dan Sinclair <dsinclair@chromium.org>
Commit-Queue: Ben Clayton <bclayton@chromium.org>
Kokoro: Ben Clayton <bclayton@chromium.org>
diff --git a/src/tint/ast/builtin_texture_helper_test.h b/src/tint/ast/builtin_texture_helper_test.h
index 7391e8c..7130b9a 100644
--- a/src/tint/ast/builtin_texture_helper_test.h
+++ b/src/tint/ast/builtin_texture_helper_test.h
@@ -24,6 +24,12 @@
 
 namespace tint::ast::builtin::test {
 
+/// The name of the texture global variable used by the tests.
+static constexpr const char* kTextureName = "Texture";
+
+/// The name of the sampler global variable used by the tests.
+static constexpr const char* kSamplerName = "Sampler";
+
 enum class TextureKind { kRegular, kDepth, kDepthMultisampled, kMultisampled, kStorage };
 enum class TextureDataType { kF32, kU32, kI32 };