Replace TextureType::(Is|As)Multisampled with Castable

Change-Id: I9a0e2ba4c6b0950134cef4b291cd1ba5cae1198c
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/34277
Reviewed-by: dan sinclair <dsinclair@chromium.org>

src/ast/function.cc

@@ -18,6 +18,7 @@
 
 #include "src/ast/decorated_variable.h"
 #include "src/ast/stage_decoration.h"
+#include "src/ast/type/multisampled_texture_type.h"
 #include "src/ast/type/texture_type.h"
 #include "src/ast/workgroup_decoration.h"
 
@@ -315,7 +316,7 @@ Function::ReferencedSampledTextureVariablesImpl(bool multisampled) const {
     }
 
     if ((multisampled &&
-         !unwrapped_type->As<ast::type::TextureType>()->IsMultisampled()) ||
+         !unwrapped_type->Is<ast::type::MultisampledTextureType>()) ||
         (!multisampled &&
          !unwrapped_type->As<ast::type::TextureType>()->IsSampled())) {
       continue;

src/ast/type/multisampled_texture_type.cc

@@ -32,9 +32,6 @@ MultisampledTextureType::MultisampledTextureType(MultisampledTextureType&&) =
 
 MultisampledTextureType::~MultisampledTextureType() = default;
 
-bool MultisampledTextureType::IsMultisampled() const {
-  return true;
-}
 
 std::string MultisampledTextureType::type_name() const {
   std::ostringstream out;

src/ast/type/multisampled_texture_type.h

@@ -35,9 +35,6 @@ class MultisampledTextureType
   MultisampledTextureType(MultisampledTextureType&&);
   ~MultisampledTextureType() override;
 
-  /// @returns true if the type is a sampled texture type
-  bool IsMultisampled() const override;
-
   /// @returns the subtype of the sampled texture
   Type* type() const { return type_; }
 

src/ast/type/multisampled_texture_type_test.cc

@@ -58,7 +58,7 @@ TEST_F(MultisampledTextureTypeTest, IsTextureType) {
   MultisampledTextureType s(TextureDimension::kCube, &f32);
   TextureType* ty = &s;
   EXPECT_FALSE(ty->Is<DepthTextureType>());
-  EXPECT_TRUE(ty->IsMultisampled());
+  EXPECT_TRUE(ty->Is<MultisampledTextureType>());
   EXPECT_FALSE(ty->IsSampled());
   EXPECT_FALSE(ty->IsStorage());
 }

src/ast/type/texture_type.cc

@@ -60,9 +60,6 @@ TextureType::TextureType(TextureType&&) = default;
 
 TextureType::~TextureType() = default;
 
-bool TextureType::IsMultisampled() const {
-  return false;
-}
 bool TextureType::IsStorage() const {
   return false;
 }
@@ -70,11 +67,6 @@ bool TextureType::IsSampled() const {
   return false;
 }
 
-const MultisampledTextureType* TextureType::AsMultisampled() const {
-  assert(IsMultisampled());
-  return static_cast<const MultisampledTextureType*>(this);
-}
-
 const SampledTextureType* TextureType::AsSampled() const {
   assert(IsSampled());
   return static_cast<const SampledTextureType*>(this);
@@ -85,11 +77,6 @@ const StorageTextureType* TextureType::AsStorage() const {
   return static_cast<const StorageTextureType*>(this);
 }
 
-MultisampledTextureType* TextureType::AsMultisampled() {
-  assert(IsMultisampled());
-  return static_cast<MultisampledTextureType*>(this);
-}
-
 SampledTextureType* TextureType::AsSampled() {
   assert(IsSampled());
   return static_cast<SampledTextureType*>(this);

src/ast/type/texture_type.h

@@ -24,8 +24,6 @@ namespace tint {
 namespace ast {
 namespace type {
 
-class DepthTextureType;
-class MultisampledTextureType;
 class SampledTextureType;
 class StorageTextureType;
 
@@ -63,22 +61,16 @@ class TextureType : public Castable<TextureType, Type> {
   /// @returns the texture dimension
   TextureDimension dim() const { return dim_; }
 
-  /// @returns ture if this is a multisampled texture
-  virtual bool IsMultisampled() const;
   /// @returns true if this is a storage texture
   virtual bool IsStorage() const;
   /// @returns true if this is a sampled texture
   virtual bool IsSampled() const;
 
-  /// @returns the texture as a multisampled texture
-  const MultisampledTextureType* AsMultisampled() const;
   /// @returns the texture as a sampled texture
   const SampledTextureType* AsSampled() const;
   /// @returns the texture as a storage texture
   const StorageTextureType* AsStorage() const;
 
-  /// @returns the texture as a multisampled texture
-  MultisampledTextureType* AsMultisampled();
   /// @returns the texture as a sampled texture
   SampledTextureType* AsSampled();
   /// @returns the texture as a storage texture