GN: Check if targets with precompiled headers use unsupported toolchains.

tools/gn/source_file_type.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef TOOLS_GN_SOURCE_FILE_TYPE_H_
 #define TOOLS_GN_SOURCE_FILE_TYPE_H_
 
 class SourceFile;
 
 // This should be sequential integers starting from 0 so they can be used as
@@ skipping 10 matching lines @@
   SOURCE_RC,
   SOURCE_O,  // Object files can be inputs, too. Also counts .obj.
   SOURCE_DEF,
 
   // Must be last.
   SOURCE_NUMTYPES,
 };
 
 SourceFileType GetSourceFileType(const SourceFile& file);
 
+// Represents a set of tool types.
+class SourceFileTypeSet {
+ public:
+  SourceFileTypeSet() {
+    for (auto& flag : flags_)
+      flag = 0;
+  }
+
+  void Set(SourceFileType type) { flags_[static_cast<int>(type)] = true; }
+  bool Get(SourceFileType type) const { return flags_[static_cast<int>(type)]; }
+
+ private:
+  bool flags_[static_cast<int>(SOURCE_NUMTYPES)];
+};
+
 #endif  // TOOLS_GN_SOURCE_FILE_TYPE_H_