Background compilation work:

runtime/vm/compiler.h

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_COMPILER_H_
 #define VM_COMPILER_H_
 
 #include "vm/allocation.h"
 #include "vm/growable_array.h"
 #include "vm/runtime_entry.h"
@@ skipping 26 matching lines @@
 
   void set_result_code(const Code& value) { result_code_ = value.raw(); }
   const Code& result_code() const { return result_code_; }
 
   uint32_t cha_invalidation_gen() const { return cha_invalidation_gen_; }
   uint32_t field_invalidation_gen() const { return field_invalidation_gen_; }
   uint32_t prefix_invalidation_gen() const { return prefix_invalidation_gen_; }
 
   void SetFromQElement(QueueElement* value);
 
+  void SetLeafClasses(const GrowableArray<Class*>& leaf_classes);
+  void SetGuardedFields(const ZoneGrowableArray<const Field*>& guarded_fields);
+  void SetDeoptimizeDependentFields(const GrowableArray<const Field*>& fields);
+
+  const Array& leaf_classes() const { return leaf_classes_; }
+  const Array& guarded_fields() const { return guarded_fields_; }
+  const Array& deoptimize_dependent_fields() const {
+    return deoptimize_dependent_fields_;
+  }
+
   // Returns true if all relevant gen-counts are current and code is valid.
   bool IsValid() const;
 
   // Remove gen-counts from validation check.
   void ClearCHAInvalidationGen() {
     cha_invalidation_gen_ = Isolate::kInvalidGen;
   }
   void ClearFieldInvalidationGen() {
     field_invalidation_gen_ = Isolate::kInvalidGen;
   }
   void ClearPrefixInvalidationGen() {
     prefix_invalidation_gen_ = Isolate::kInvalidGen;
   }
 
   void PrintValidity() const;
 
  private:
   Code& result_code_;
+  Array& leaf_classes_;
+  Array& guarded_fields_;
+  Array& deoptimize_dependent_fields_;
   uint32_t cha_invalidation_gen_;
   uint32_t field_invalidation_gen_;
   uint32_t prefix_invalidation_gen_;
 };
 
 
 class Compiler : public AllStatic {
  public:
   static const intptr_t kNoOSRDeoptId = Thread::kNoDeoptId;
 
@@ skipping 118 matching lines @@
 
   BackgroundCompilationQueue* function_queue_;
   BackgroundCompilationQueue* result_queue_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(BackgroundCompiler);
 };
 
 }  // namespace dart
 
 #endif  // VM_COMPILER_H_