Delete unused files

A couple more headers that should have been deleted in 95d4077.

Change-Id: Icd051842d0ff143ea74eb62c636506dc2a955681
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/45380
Auto-Submit: James Price <jrprice@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
Commit-Queue: Ben Clayton <bclayton@google.com>
diff --git a/src/ast/function_decoration.h b/src/ast/function_decoration.h
deleted file mode 100644
index 5a75e0e..0000000
--- a/src/ast/function_decoration.h
+++ /dev/null
@@ -1,48 +0,0 @@
-// Copyright 2020 The Tint Authors.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-#ifndef SRC_AST_FUNCTION_DECORATION_H_
-#define SRC_AST_FUNCTION_DECORATION_H_
-
-#include <vector>
-
-#include "src/ast/decoration.h"
-
-namespace tint {
-namespace ast {
-
-/// A decoration attached to a function
-class FunctionDecoration : public Castable<FunctionDecoration, Decoration> {
- public:
-  /// The kind of decoration that this type represents
-  static constexpr const DecorationKind Kind = DecorationKind::kFunction;
-
-  ~FunctionDecoration() override;
-
-  /// @return the decoration kind
-  DecorationKind GetKind() const override;
-
- protected:
-  /// Constructor
-  /// @param source the source of this decoration
-  explicit FunctionDecoration(const Source& source);
-};
-
-/// A list of function decorations
-using FunctionDecorationList = std::vector<FunctionDecoration*>;
-
-}  // namespace ast
-}  // namespace tint
-
-#endif  // SRC_AST_FUNCTION_DECORATION_H_
diff --git a/src/ast/struct_decoration.h b/src/ast/struct_decoration.h
deleted file mode 100644
index 31c8e32..0000000
--- a/src/ast/struct_decoration.h
+++ /dev/null
@@ -1,48 +0,0 @@
-// Copyright 2020 The Tint Authors.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-#ifndef SRC_AST_STRUCT_DECORATION_H_
-#define SRC_AST_STRUCT_DECORATION_H_
-
-#include <vector>
-
-#include "src/ast/decoration.h"
-
-namespace tint {
-namespace ast {
-
-/// The struct decorations
-class StructDecoration : public Castable<StructDecoration, Decoration> {
- public:
-  /// The kind of decoration that this type represents
-  static constexpr const DecorationKind Kind = DecorationKind::kStruct;
-
-  ~StructDecoration() override;
-
-  /// @return the decoration kind
-  DecorationKind GetKind() const override;
-
- protected:
-  /// Constructor
-  /// @param source the source of this decoration
-  explicit StructDecoration(const Source& source);
-};
-
-/// List of struct decorations
-using StructDecorationList = std::vector<StructDecoration*>;
-
-}  // namespace ast
-}  // namespace tint
-
-#endif  // SRC_AST_STRUCT_DECORATION_H_