Add isolate tag-profile and better handling of errors

runtime/vm/thread_interrupter.h

 // Copyright (c) 2013, 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_THREAD_INTERRUPTER_H_
 #define VM_THREAD_INTERRUPTER_H_
 
 #include "vm/allocation.h"
 #include "vm/signal_handler.h"
 #include "vm/thread.h"
@@ skipping 43 matching lines @@
                                             void* data);
   // Unregister the currently running thread for interrupts.
   static void Unregister();
 
   // Get the current thread state. Will create a thread state if one hasn't
   // been allocated.
   static InterruptableThreadState* GetCurrentThreadState();
   // Get the current thread state. Will not create one if one doesn't exist.
   static InterruptableThreadState* CurrentThreadState();
 
+  // Interrupt a thread.
+  static void InterruptThread(InterruptableThreadState* thread_state);
+
  private:
   static const intptr_t kMaxThreads = 4096;
   static bool initialized_;
   static bool shutdown_;
   static bool thread_running_;
   static ThreadId interrupter_thread_id_;
   static Monitor* monitor_;
   static intptr_t interrupt_period_;
   static ThreadLocalKey thread_state_key_;
 
   static InterruptableThreadState* _EnsureThreadStateCreated();
   static void UpdateStateObject(ThreadInterruptCallback callback, void* data);
 
   static void SetCurrentThreadState(InterruptableThreadState* state);
 
-  static void InterruptThread(InterruptableThreadState* thread_state);
   static void ThreadMain(uword parameters);
 
   static void InstallSignalHandler();
 
   friend class ThreadInterrupterVisitIsolates;
 };
 
 void ThreadInterruptNoOp(const InterruptedThreadState& state, void* data);
 
 }  // namespace dart
 
 #endif  // VM_THREAD_INTERRUPTER_H_