blink_gc_plugin: detect singletons with embedded ScriptWrappables.

tools/clang/blink_gc_plugin/CollectVisitor.h

 // Copyright 2015 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_BLINK_GC_PLUGIN_COLLECT_VISITOR_H_
 #define TOOLS_BLINK_GC_PLUGIN_COLLECT_VISITOR_H_
 
 #include <vector>
 
 #include "clang/AST/AST.h"
 #include "clang/AST/RecursiveASTVisitor.h"
 
 // This visitor collects the entry points for the checker.
 class CollectVisitor : public clang::RecursiveASTVisitor<CollectVisitor> {
  public:
-  typedef std::vector<clang::CXXRecordDecl*> RecordVector;
-  typedef std::vector<clang::CXXMethodDecl*> MethodVector;
+  using RecordVector = std::vector<clang::CXXRecordDecl*>;
+  using MethodVector = std::vector<clang::CXXMethodDecl*>;
+  using SingletonVector = std::vector<clang::VarDecl*>;
 
-  CollectVisitor();
+  explicit CollectVisitor(bool check_var_decls);
 
   RecordVector& record_decls();
   MethodVector& trace_decls();
 
+  const SingletonVector& singleton_decls() const;
+
   // Collect record declarations, including nested declarations.
   bool VisitCXXRecordDecl(clang::CXXRecordDecl* record);
 
   // Collect tracing method definitions, but don't traverse method bodies.
   bool VisitCXXMethodDecl(clang::CXXMethodDecl* method);
 
+  // Collect static singleton declarations, traverses the function body.
+  bool VisitFunctionDecl(clang::FunctionDecl*);
+
  private:
+  class LocalVarsVisitor : public clang::RecursiveASTVisitor<LocalVarsVisitor> {
+   public:
+    explicit LocalVarsVisitor(CollectVisitor* parent) : parent_(parent) {}
+
+    bool VisitVarDecl(clang::VarDecl* decl);
+
+   private:
+    CollectVisitor* parent_;
+  };
+
   RecordVector record_decls_;
   MethodVector trace_decls_;
+  SingletonVector singleton_decls_;
+
+  bool check_var_decls_;
+  LocalVarsVisitor var_visitor_;
 };
 
 #endif  // TOOLS_BLINK_GC_PLUGIN_COLLECT_VISITOR_H_