Add checks for stack-allocated types and their uses in fields.

tools/clang/blink_gc_plugin/RecordInfo.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.
 
 // This file provides a wrapper for CXXRecordDecl that accumulates GC related
 // information about a class. Accumulated information is memoized and the info
 // objects are stored in a RecordCache.
 
 #ifndef TOOLS_BLINK_GC_PLUGIN_RECORD_INFO_H_
 #define TOOLS_BLINK_GC_PLUGIN_RECORD_INFO_H_
@@ skipping 95 matching lines @@
 
   Edge* CreateEdge(const clang::Type* type);
 
   RecordCache* cache_;
   clang::CXXRecordDecl* record_;
   const std::string name_;
   TracingStatus fields_need_tracing_;
   Bases* bases_;
   Fields* fields_;
 
+  enum CachedBool { kFalse = 0, kTrue = 1, kNotComputed = 2 };
+  CachedBool is_stack_allocated_;
+
   bool determined_trace_methods_;
   clang::CXXMethodDecl* trace_method_;
   clang::CXXMethodDecl* trace_dispatch_method_;
   clang::CXXMethodDecl* finalize_dispatch_method_;
 
   bool is_gc_derived_;
   clang::CXXBasePaths* base_paths_;
 
   friend class RecordCache;
 };
@@ skipping 29 matching lines @@
       }
     }
   }
 
  private:
   typedef std::map<clang::CXXRecordDecl*, RecordInfo> Cache;
   Cache cache_;
 };
 
 #endif  // TOOLS_BLINK_GC_PLUGIN_RECORD_INFO_H_