Fix compilation.

src/isolate.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1090 matching lines @@
     max_available_threads_ = value;
   }
 
   bool concurrent_recompilation_enabled() {
     // Thread is only available with flag enabled.
     ASSERT(optimizing_compiler_thread_ == NULL ||
            FLAG_concurrent_recompilation);
     return optimizing_compiler_thread_ != NULL;
   }
 
-  bool concurrent_osr_enabled() {
+  bool concurrent_osr_enabled() const {
     // Thread is only available with flag enabled.
     ASSERT(optimizing_compiler_thread_ == NULL ||
            FLAG_concurrent_recompilation);
     return optimizing_compiler_thread_ != NULL && FLAG_concurrent_osr;
   }
 
   OptimizingCompilerThread* optimizing_compiler_thread() {
     return optimizing_compiler_thread_;
   }
 
-  bool num_sweeper_threads() {
+  int num_sweeper_threads() const {
     return num_sweeper_threads_;
   }
 
   SweeperThread** sweeper_threads() {
     return sweeper_thread_;
   }
 
   // PreInits and returns a default isolate. Needed when a new thread tries
   // to create a Locker for the first time (the lock itself is in the isolate).
   // TODO(svenpanne) This method is on death row...
@@ skipping 454 matching lines @@
   }
 
   EmbeddedVector<char, 128> filename_;
   FILE* file_;
   int scope_depth_;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_ISOLATE_H_